**5. HPV associated oral injuries**

HPV infection range from asymptomatic to visible lesions, which can be benign or malignant [6]. The most common oral manifestations are described below:

## **5.1. Condyloma acuminatum**

The lesion is caused by the abnormal proliferation of a squamous stratified epithelium [23]. Formerly it was believed that the only transmission route was by sexual contact, but now it is known that there are other routes, such as self-inoculation and mother-fetus transmission [15]. However, sexual contact remains the main route of transmission (20%) [23], and people who carry these lesions and practice oral sex have a 50% chance to acquiring oral condyloma. The incubation period range from 3 weeks to an undetermined period of time; after that, clinic progression will depend on cell permissiveness, virus type and host immune situation [24].

Differential diagnoses include oral squamous papilloma, verruca vulgaris, molluscum contagiosum, seborrheic keratosis, lichen planus and oral squamous cell carcinoma (OSCC)

*from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

**Figure 1.** Condyloma acuminatum. Rose-colored nodule with a cauliflower-like surface in the floor of the mouth (**A**; inset – closer view). Lesion on the hard palate (B; inset – closer view). Microscopically, panoramic view of acanthosis with papillary folds, parakeratosis and elongation of rete ridges (**C**, **D**) (HE, Objective 2.5x). *Clinical images obtained*

Oral HPV Related Diseases: A Review and an Update 21

Condyloma acuminatum treatment is not always necessary. For 20-30% of HPV patients, lesions are self-limited and resolve spontaneously within six months, while for 60% of them, lesions may regress in a year. Relapses affect 20-30% of patients undergoing treatment, and they may reappear on the same sites or on different locations [24]. The choice of therapy is based on a range of factors, such as lesions size, aspect, number and sites. Other factors of equal significance include patient preference, costs, and adverse effects [23]. Commonly, lesions have been treated by excisional surgery, but in the last years a wider choice of treatments have become available, e.g., cryotherapy, electro cauterization and CO2 laser. Other options include caustic agents, such as trichloroacetic acid, podophyllin and 5-flourouacil which may cause

[15].

tissue destruction [23].

Condyloma acuminatum has tropism to tongue, lips, palate and mouth floor. Clinically, it is described as little pinkish or whitish nodules which proliferate in papillary projections that might be either pedicle or sessile. Outline surfaces present even more evident cauliflower shapes than papilloma, mainly when they converge (Figure 1 – A, B).

Histologically, oral condylomata are typically papillary proliferations of squamous epithelium with prominent acanthosis and parakeratin that line deep crypts, similar to their counterparts in the lower genital tract. Koilocytosis is the classic diagnostic feature, consisting of cells with perinuclear halos of various sizes and accompanied by variability in nuclear size and chro‐ maticity, as well as nuclear membrane irregularity. These features are most prominent toward the surface of the lesion (Figure 1 – C, D) [25].

HPV presence was first determined by immunohistochemistry and later by hybridization with 75 to 85% of positivity [15]. The most involved types are 6 and 11 [5, 15, 18].

Smoking may pose a lower risk for infection with high risk oral and oropharyngeal HPV than it was previously believed probably because the oral mucosa keratinization makes it stronger against minor traumas and consequently HPV infection. On the other hand, high levels of alcohol consumption have been linked to a higher risk of HPV positivity, but this association

Normally, people acquire HPV during their adolescent years, or when they approach their twenties, when they start their sexual life. An immune competent person can suppress HPV

Among the leading protective factors, saliva stands out. It is composed of lysozymes, lacto‐ ferrin, IgA and cytokines which seems to be the reason behind low HPV transmission through self-inoculation, oral sex, and the virtually inexistence of transmission through kissing. It has been suggested that regular consumption of carotenoids would contribute to make HPV persistence less likely, and a high consumption of folic acid would reduce the risk of HPV

HPV infection range from asymptomatic to visible lesions, which can be benign or malignant

The lesion is caused by the abnormal proliferation of a squamous stratified epithelium [23]. Formerly it was believed that the only transmission route was by sexual contact, but now it is known that there are other routes, such as self-inoculation and mother-fetus transmission [15]. However, sexual contact remains the main route of transmission (20%) [23], and people who carry these lesions and practice oral sex have a 50% chance to acquiring oral condyloma. The incubation period range from 3 weeks to an undetermined period of time; after that, clinic progression will depend on cell permissiveness, virus type and host immune situation [24]. Condyloma acuminatum has tropism to tongue, lips, palate and mouth floor. Clinically, it is described as little pinkish or whitish nodules which proliferate in papillary projections that might be either pedicle or sessile. Outline surfaces present even more evident cauliflower

Histologically, oral condylomata are typically papillary proliferations of squamous epithelium with prominent acanthosis and parakeratin that line deep crypts, similar to their counterparts in the lower genital tract. Koilocytosis is the classic diagnostic feature, consisting of cells with perinuclear halos of various sizes and accompanied by variability in nuclear size and chro‐ maticity, as well as nuclear membrane irregularity. These features are most prominent toward

HPV presence was first determined by immunohistochemistry and later by hybridization with

or even eliminate it, and suppressed HPV may be kept subclinical for years [8].

needs further research in order to be more fully established [68].

[6]. The most common oral manifestations are described below:

shapes than papilloma, mainly when they converge (Figure 1 – A, B).

75 to 85% of positivity [15]. The most involved types are 6 and 11 [5, 15, 18].

the surface of the lesion (Figure 1 – C, D) [25].

infection [4].

20 Trends in Infectious Diseases

**5. HPV associated oral injuries**

**5.1. Condyloma acuminatum**

**Figure 1.** Condyloma acuminatum. Rose-colored nodule with a cauliflower-like surface in the floor of the mouth (**A**; inset – closer view). Lesion on the hard palate (B; inset – closer view). Microscopically, panoramic view of acanthosis with papillary folds, parakeratosis and elongation of rete ridges (**C**, **D**) (HE, Objective 2.5x). *Clinical images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

Differential diagnoses include oral squamous papilloma, verruca vulgaris, molluscum contagiosum, seborrheic keratosis, lichen planus and oral squamous cell carcinoma (OSCC) [15].

Condyloma acuminatum treatment is not always necessary. For 20-30% of HPV patients, lesions are self-limited and resolve spontaneously within six months, while for 60% of them, lesions may regress in a year. Relapses affect 20-30% of patients undergoing treatment, and they may reappear on the same sites or on different locations [24]. The choice of therapy is based on a range of factors, such as lesions size, aspect, number and sites. Other factors of equal significance include patient preference, costs, and adverse effects [23]. Commonly, lesions have been treated by excisional surgery, but in the last years a wider choice of treatments have become available, e.g., cryotherapy, electro cauterization and CO2 laser. Other options include caustic agents, such as trichloroacetic acid, podophyllin and 5-flourouacil which may cause tissue destruction [23].

#### **5.2. Verruca vulgaris (Common wart)**

Verruca vulgaris, also known as common wart is one of the most common lesions affecting mainly children [15], but seldom on oral mucosa [6].

particularly in the grooves between the elongated connective tissue papillae. Koilocytes may be seen. In the connective tissue, some dilated capillaries and a slight infiltration with lym‐

Oral HPV Related Diseases: A Review and an Update 23

Immunohistochemical methods and hybridization tests showed HPV presence in 43 to 100%

Most oral warts are self-limited, and resolve within 2 years. Aesthetic discomfort or bite injuries induce patients to look for treatment. Some treatment techniques are cauterization, surgical removal, liquid nitrogen cryotherapy, local hyperthermia, topic 5-fluoracil, CO2 laser, salicylic

Oral squamous papilloma (OSP) is a benign tumor that may occur in all ages, but it more commonly affects adults between 30 and 50 years old [15]. It is mainly related to HPV 6 and 11 [15, 18]. In adults, the lesion is usually located in the oral mucosa, mostly on palate and tongue, while in children the laryngotracheobronchial complex is a more common site [27]. OSP affects the soft palate, the lingual frenulum as well as the lower lip [15] and the uvula [27], most often presenting as a single, small lesion smaller than 1 cm, with exophytic growth and a wide basis or pedicle. On histopathology the pattern of epithelial proliferation repeats features described in the previous lesions, with squamous cell acanthosis, hyperkeratosis and a centrally disposed fibrovascular core.(Figure 3 – A, E). Koilocytosis may be present or not. Oral squamous papilloma may be isolated or multiple-recurring, which is more likely to affect immunosuppressed patients, such as HIV-positive patients. Multiple-recurring papilloma is also more likely to be malignant [27] and tends to relapse more often [28]. Differential diagnoses include exophytic carcinoma, verrucous carcinoma and condyloma acuminatum [27]. Surgical removal is the first choice of treatment, but electrocauterization, cryosurgery and

Focal epithelial hyperplasia (FEH) or Heck disease was first described in 1965 [15] and can affect all age groups [29], but it is more common in children and adolescents (3 to 18 years) [30]. Malnutrition, poor hygiene and low social condition as well as genetic background also play

FEH shows a benign epithelial growth and commonly affects oral mucosa, lips, tongue [18], particularly the lower lip and more rarely the palate, floor of the mouth and oropharynx [30]. Clinically it presents as multiple papules (3 – 10 mm) [30] that tend to converge. They are characteristically nodular, sessile, circumscribed, painless and soft masses on oral mucosa. Color may range from pale pink to normal mucosa [15, 29- 31]. (Figure 4 – A, B). The diagnosis

Microscopically it shows epithelial hyperplasia, acanthosis, mild parakeratosis and anasto‐ mosing rete ridges. Superficial layers of the epithelial tissue contain cytophatic changes

phocytes are usually seen (Figure 2 C, D) [26]

acid, squaric acid, interferon and wart material implantation [18].

interferon injections are other effective treatment courses [8].

**5.4. Focal epithelial hyperplasia (Heck disease)**

an important role [31] in lesion development.

is both clinical and histological [30, 32].

of the studied lesions [15].

**5.3. Oral squamous papilloma**

It is usually found on lips, hard palate, gingival, and tongue dorsal surface [15], but especially on lips and tongue [18] (Figure 2 - A, B). Differential diagnoses is made with oral squamous papilloma and condyloma acuminatum [15, 18].

**Figure 2.** Verruca vulgaris. Exophytic lesion with hyperkeratotic surface, forming finger projections in the left commis‐ sure of the lip (**A**, circle). Lesion on the lower lip (**B**). Microscopically, panoramic view of acanthosis with papillary folds, hyperortoparakeratosis and elongation of rete ridges (**C**; HE, Objective 4x). Koilocitosis (**D**; HE, Objective 20x). *Clinical images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

Histologically, verruca vulgaris show an almost symmetrical structure, with elongated rete ridges that are shorter at the periphery than in central area. Thin elongated connective tissue papillae form papillomatosis. The cryptoform surface shows a conspicuous hyperkeratiniza‐ tion, predominantly composed of orthokeratin. The stratum granulosum is often pronounced, particularly in the grooves between the elongated connective tissue papillae. Koilocytes may be seen. In the connective tissue, some dilated capillaries and a slight infiltration with lym‐ phocytes are usually seen (Figure 2 C, D) [26]

Immunohistochemical methods and hybridization tests showed HPV presence in 43 to 100% of the studied lesions [15].

Most oral warts are self-limited, and resolve within 2 years. Aesthetic discomfort or bite injuries induce patients to look for treatment. Some treatment techniques are cauterization, surgical removal, liquid nitrogen cryotherapy, local hyperthermia, topic 5-fluoracil, CO2 laser, salicylic acid, squaric acid, interferon and wart material implantation [18].

### **5.3. Oral squamous papilloma**

**5.2. Verruca vulgaris (Common wart)**

22 Trends in Infectious Diseases

mainly children [15], but seldom on oral mucosa [6].

papilloma and condyloma acuminatum [15, 18].

Verruca vulgaris, also known as common wart is one of the most common lesions affecting

It is usually found on lips, hard palate, gingival, and tongue dorsal surface [15], but especially on lips and tongue [18] (Figure 2 - A, B). Differential diagnoses is made with oral squamous

**Figure 2.** Verruca vulgaris. Exophytic lesion with hyperkeratotic surface, forming finger projections in the left commis‐ sure of the lip (**A**, circle). Lesion on the lower lip (**B**). Microscopically, panoramic view of acanthosis with papillary folds, hyperortoparakeratosis and elongation of rete ridges (**C**; HE, Objective 4x). Koilocitosis (**D**; HE, Objective 20x). *Clinical images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

Histologically, verruca vulgaris show an almost symmetrical structure, with elongated rete ridges that are shorter at the periphery than in central area. Thin elongated connective tissue papillae form papillomatosis. The cryptoform surface shows a conspicuous hyperkeratiniza‐ tion, predominantly composed of orthokeratin. The stratum granulosum is often pronounced, Oral squamous papilloma (OSP) is a benign tumor that may occur in all ages, but it more commonly affects adults between 30 and 50 years old [15]. It is mainly related to HPV 6 and 11 [15, 18]. In adults, the lesion is usually located in the oral mucosa, mostly on palate and tongue, while in children the laryngotracheobronchial complex is a more common site [27].

OSP affects the soft palate, the lingual frenulum as well as the lower lip [15] and the uvula [27], most often presenting as a single, small lesion smaller than 1 cm, with exophytic growth and a wide basis or pedicle. On histopathology the pattern of epithelial proliferation repeats features described in the previous lesions, with squamous cell acanthosis, hyperkeratosis and a centrally disposed fibrovascular core.(Figure 3 – A, E). Koilocytosis may be present or not.

Oral squamous papilloma may be isolated or multiple-recurring, which is more likely to affect immunosuppressed patients, such as HIV-positive patients. Multiple-recurring papilloma is also more likely to be malignant [27] and tends to relapse more often [28]. Differential diagnoses include exophytic carcinoma, verrucous carcinoma and condyloma acuminatum [27]. Surgical removal is the first choice of treatment, but electrocauterization, cryosurgery and interferon injections are other effective treatment courses [8].

#### **5.4. Focal epithelial hyperplasia (Heck disease)**

Focal epithelial hyperplasia (FEH) or Heck disease was first described in 1965 [15] and can affect all age groups [29], but it is more common in children and adolescents (3 to 18 years) [30]. Malnutrition, poor hygiene and low social condition as well as genetic background also play an important role [31] in lesion development.

FEH shows a benign epithelial growth and commonly affects oral mucosa, lips, tongue [18], particularly the lower lip and more rarely the palate, floor of the mouth and oropharynx [30]. Clinically it presents as multiple papules (3 – 10 mm) [30] that tend to converge. They are characteristically nodular, sessile, circumscribed, painless and soft masses on oral mucosa. Color may range from pale pink to normal mucosa [15, 29- 31]. (Figure 4 – A, B). The diagnosis is both clinical and histological [30, 32].

Microscopically it shows epithelial hyperplasia, acanthosis, mild parakeratosis and anasto‐ mosing rete ridges. Superficial layers of the epithelial tissue contain cytophatic changes

**Figure 3.** Oral squamous papilloma. Exophytic lesion with hyperkeratotic whitish surface, forming finger projections on the dorsum of the tongue (**A-B**). Lesion on the inferior surface of the tongue (**C**). Lesion on the lower lip (**D**). Micro‐ scopically, panoramic view of acanthosis with papillary folds, hyperortoparakeratosis, elongation of rete ridges and a centrally disposed fibrovascular core (**E**; HE, Objective 2.5x). Clinical images obtained from the archives of the Stomatol‐ *ogy Specialization at Odontoclínica Central do Exército (OCEx).*

(koilocytosis) and apoptotic or dyskeratotic cells with an apparent mitotic appearance (mitosoid cells) (Figure 4 – C, D) [30].

mucosa [33-, 35]. OLP prevalence ranges from 0, 5% to 4% [35] and mainly affects the female population [33-35]. The most prevalent age is between 30 to 60 years old, although occurrence in children and adolescents seems to be on the rise [35]. In around 15% of the cases the skin is affected and this number increases to around 85% of cases affecting the mucosa, particularly the oral and genital mucosa. The oral mucosa is affected in 20% to 30% of the cases. Besides being more common, OLP is more resistant to treatment than skin OLP [34]. A possible relationship between OLP to Hepatitis C has been hypothesized, but it has not been clearly

**Figure 4.** Focal Epithelial Hyperplasia. Multiple flat and coalescent papules on the lower lip mucosa (**A-B**). Microscopi‐ cally, panoramic view showing acanthosis and irregular elongation and anastomosis of rete ridges (**C;** HE, Objective 2.5x). Classic "mitosoid" figure (**D**; HE, Objective 40x). *Clinical images obtained from the archives of the Stomatology*

Oral HPV Related Diseases: A Review and an Update 25

Diagnoses depend on clinic manifestation as well as histopathology results [35]. OLP lesions are usually bilateral and symmetric affecting areas the oral mucosa, gingiva as well as the

The lesions may be single or multiple and may present in a wide range of forms- cauliflowerlike, striated or annular. Long-time evolution of a lesion is usually atrophic, and when the lesion is located on the tongue it may cause papillae loss and modify gustation (Figure 5 – G,

dorsum of the tongue and the lip mucosa (Figure 5 – A, F ).

F ). Extensive lesions are also more painful [35].

*Specialization at Odontoclínica Central do Exército (OCEx).*

established.

FEH has a steady association with HPV infection, and the most common types are 13 and 32 [15, 29]; they account for approximately 90% of infections [30, 32]. HPV-32 might be found in other type of lesions, but never out of the oral region [15]. Both HPV-1 and 11 are rare and show potential for malignancy. So far, the only malignant transformation reported has been found with HPV-24 [32].

Differential diagnoses include condyloma, viral warts, neuroma, white sponge nevus, oral papillomatosis, [30] and inflammatory fibrous hyperplasia.

FEH normally regresses spontaneously in a few months or years, but it can take longer [30]. Thus, treatment is often chosen to mitigate aesthetic problems or repeated bite injuries [31]. The most effective methods are surgical excision, electrocoagulation, cryotherapy [31], CO2 laser and interferon [30].

#### **5.5. Oral lichen planus**

Oral lichen planus (OLP) is a common chronic immunomediated disease [18, 33, 34] of unknown etiology seemingly related to HPV in some lesions [18], affecting the skin and the

**Figure 4.** Focal Epithelial Hyperplasia. Multiple flat and coalescent papules on the lower lip mucosa (**A-B**). Microscopi‐ cally, panoramic view showing acanthosis and irregular elongation and anastomosis of rete ridges (**C;** HE, Objective 2.5x). Classic "mitosoid" figure (**D**; HE, Objective 40x). *Clinical images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

(koilocytosis) and apoptotic or dyskeratotic cells with an apparent mitotic appearance

**Figure 3.** Oral squamous papilloma. Exophytic lesion with hyperkeratotic whitish surface, forming finger projections on the dorsum of the tongue (**A-B**). Lesion on the inferior surface of the tongue (**C**). Lesion on the lower lip (**D**). Micro‐ scopically, panoramic view of acanthosis with papillary folds, hyperortoparakeratosis, elongation of rete ridges and a centrally disposed fibrovascular core (**E**; HE, Objective 2.5x). Clinical images obtained from the archives of the Stomatol‐

FEH has a steady association with HPV infection, and the most common types are 13 and 32 [15, 29]; they account for approximately 90% of infections [30, 32]. HPV-32 might be found in other type of lesions, but never out of the oral region [15]. Both HPV-1 and 11 are rare and show potential for malignancy. So far, the only malignant transformation reported has been

Differential diagnoses include condyloma, viral warts, neuroma, white sponge nevus, oral

FEH normally regresses spontaneously in a few months or years, but it can take longer [30]. Thus, treatment is often chosen to mitigate aesthetic problems or repeated bite injuries [31]. The most effective methods are surgical excision, electrocoagulation, cryotherapy [31], CO2

Oral lichen planus (OLP) is a common chronic immunomediated disease [18, 33, 34] of unknown etiology seemingly related to HPV in some lesions [18], affecting the skin and the

(mitosoid cells) (Figure 4 – C, D) [30].

*ogy Specialization at Odontoclínica Central do Exército (OCEx).*

papillomatosis, [30] and inflammatory fibrous hyperplasia.

found with HPV-24 [32].

24 Trends in Infectious Diseases

laser and interferon [30].

**5.5. Oral lichen planus**

mucosa [33-, 35]. OLP prevalence ranges from 0, 5% to 4% [35] and mainly affects the female population [33-35]. The most prevalent age is between 30 to 60 years old, although occurrence in children and adolescents seems to be on the rise [35]. In around 15% of the cases the skin is affected and this number increases to around 85% of cases affecting the mucosa, particularly the oral and genital mucosa. The oral mucosa is affected in 20% to 30% of the cases. Besides being more common, OLP is more resistant to treatment than skin OLP [34]. A possible relationship between OLP to Hepatitis C has been hypothesized, but it has not been clearly established.

Diagnoses depend on clinic manifestation as well as histopathology results [35]. OLP lesions are usually bilateral and symmetric affecting areas the oral mucosa, gingiva as well as the dorsum of the tongue and the lip mucosa (Figure 5 – A, F ).

The lesions may be single or multiple and may present in a wide range of forms- cauliflowerlike, striated or annular. Long-time evolution of a lesion is usually atrophic, and when the lesion is located on the tongue it may cause papillae loss and modify gustation (Figure 5 – G, F ). Extensive lesions are also more painful [35].

According to Silverman's classification OLP may be presented as reticular, erosive and atrophic forms [33]. Each form has its different clinic evolution and determines different intensity and duration, with the possibility of evolving from one form into another [35].

Oral HPV Related Diseases: A Review and an Update 27

On histopathology, we may find acanthosis in keratotic lesions, and atrophy in older lesions. Two important findings are hydropic degeneration of the basal layer, as well as a strong subepithelial lymphocytic infiltrate (Figure 5 – G, H). Those lesions that present dysplasia should not be classified as OLP [36, 37]. Biopsy should be preferably performed on keratotic areas, however this might be a complicated intervention when the patient has extensive oral candidiasis [34, 35]. Some other pathologic entities may present similar histopathologic features, such as lichenoid reaction, which is similar to lichen planus, but usually is related to

The conditions that may be considered as differential diagnosis of OLP include the reticular form which should be distinguished from systemic lupus erythematosus, candidiasis, traumatic lesions, secondary syphilis, hairy leukoplakia and incipient OSCC. The erosive form should be distinguished from aphthae, mucous membrane pemphigoid, pemphigus vulgaris, drug reaction, polymorphic erythema and systemic lupus erythematosus acute lesions [35].

Malignant transformation is reported for OLP, however, a current tendency is to consider those lesions that do not fulfill established clinical and pathologic criteria for OLP as oral lichenoid lesions. These lesions mimic OLP and would be the ones truly at risk of becom‐

Treatment does not assure cure, for unknown reasons, but it does reduce symptoms, particular when they are severe, atrophic and widespread. Unlike the asymptomatic reticular form, erosive lesions need prompt symptomatic treatment. Oral hygiene reduces inflammatory lesions and topic corticosteroids may be used in the form of mouth wash. Calcineurin inhibitor, a topic immunosuppressive agent, and topic retinoid, such as imiquimod, are other treatment

Leukoplakia is considered a premalignant lesion or potentially malignant disorder on oral cavity, and reported rates of development into malignancy vary widely depending on the method of diagnosis and definition criteria used for oral leukoplakia [38]. The most common malignant transformation is into oral squamous cell carcinoma (OSCC) [38, 39], with percen‐

Oral leukoplakia prevalence ranges from 0, 4 to 0, 7%, and there is no variability related to gender. However, some researchers believe that prevalence among women is higher [38].

Etiology is uncertain; however smoking along with alcohol consumption is pointed as the main risk factors. There are possible cofactors, such as candidiasis, HPV and more recently Epstain-Barr virus (EBV) has been associated with these lesions in imunossupressed patients [38]. EBV

options, with the latter being used together with topic corticosteroids [33-35].

amalgam fillings or certain medicines [33, 34].

ing a OSCC [36, 37].

**5.6. Oral leukoplakia**

tages ranging from 3 to 37% [38].

The most prevalent and commonly found HPV types are 11 and 16 [18].

**Figure 5.** Oral lichen planus. Most prominent features are bilateral white striae in buccal mucosa, with certain symme‐ try (**A-B**). Gingiva may also be affected (**C-D**) (\*) and it may show atrophic symptomatic spots surrounded by Wickham striae (arrows). When it affects the tongue, it is not as typical (**E-F**) and may be confused with oral leukoplakia or smoker's tongue. Microscopically a strong sub epithelial lymphocytic infiltrate should be present (**C**; HE, Objective 10x), in association with degeneration of the basal layer (**D**; HE, Objective 20x) and absence of epithelial dyspla‐ sia..*Clinical images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

According to Silverman's classification OLP may be presented as reticular, erosive and atrophic forms [33]. Each form has its different clinic evolution and determines different intensity and duration, with the possibility of evolving from one form into another [35].

On histopathology, we may find acanthosis in keratotic lesions, and atrophy in older lesions. Two important findings are hydropic degeneration of the basal layer, as well as a strong subepithelial lymphocytic infiltrate (Figure 5 – G, H). Those lesions that present dysplasia should not be classified as OLP [36, 37]. Biopsy should be preferably performed on keratotic areas, however this might be a complicated intervention when the patient has extensive oral candidiasis [34, 35]. Some other pathologic entities may present similar histopathologic features, such as lichenoid reaction, which is similar to lichen planus, but usually is related to amalgam fillings or certain medicines [33, 34].

The most prevalent and commonly found HPV types are 11 and 16 [18].

The conditions that may be considered as differential diagnosis of OLP include the reticular form which should be distinguished from systemic lupus erythematosus, candidiasis, traumatic lesions, secondary syphilis, hairy leukoplakia and incipient OSCC. The erosive form should be distinguished from aphthae, mucous membrane pemphigoid, pemphigus vulgaris, drug reaction, polymorphic erythema and systemic lupus erythematosus acute lesions [35].

Malignant transformation is reported for OLP, however, a current tendency is to consider those lesions that do not fulfill established clinical and pathologic criteria for OLP as oral lichenoid lesions. These lesions mimic OLP and would be the ones truly at risk of becom‐ ing a OSCC [36, 37].

Treatment does not assure cure, for unknown reasons, but it does reduce symptoms, particular when they are severe, atrophic and widespread. Unlike the asymptomatic reticular form, erosive lesions need prompt symptomatic treatment. Oral hygiene reduces inflammatory lesions and topic corticosteroids may be used in the form of mouth wash. Calcineurin inhibitor, a topic immunosuppressive agent, and topic retinoid, such as imiquimod, are other treatment options, with the latter being used together with topic corticosteroids [33-35].

#### **5.6. Oral leukoplakia**

**Figure 5.** Oral lichen planus. Most prominent features are bilateral white striae in buccal mucosa, with certain symme‐ try (**A-B**). Gingiva may also be affected (**C-D**) (\*) and it may show atrophic symptomatic spots surrounded by Wickham striae (arrows). When it affects the tongue, it is not as typical (**E-F**) and may be confused with oral leukoplakia or smoker's tongue. Microscopically a strong sub epithelial lymphocytic infiltrate should be present (**C**; HE, Objective 10x), in association with degeneration of the basal layer (**D**; HE, Objective 20x) and absence of epithelial dyspla‐ sia..*Clinical images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército*

*(OCEx).*

26 Trends in Infectious Diseases

Leukoplakia is considered a premalignant lesion or potentially malignant disorder on oral cavity, and reported rates of development into malignancy vary widely depending on the method of diagnosis and definition criteria used for oral leukoplakia [38]. The most common malignant transformation is into oral squamous cell carcinoma (OSCC) [38, 39], with percen‐ tages ranging from 3 to 37% [38].

Oral leukoplakia prevalence ranges from 0, 4 to 0, 7%, and there is no variability related to gender. However, some researchers believe that prevalence among women is higher [38].

Etiology is uncertain; however smoking along with alcohol consumption is pointed as the main risk factors. There are possible cofactors, such as candidiasis, HPV and more recently Epstain-Barr virus (EBV) has been associated with these lesions in imunossupressed patients [38]. EBV rarely affects immunocompetent people and it does not need a specific treatment [40]. Treatment should address the underlying cause of immunosuppression.

Histological examination reveals a range of epithelium changes varying from innocuous hyperplasia to dysplasia of varying degrees [18]. However, more commonly, OL presents hyperkeratosis and epithelial hyperplasia without dysplasia [38] (Figure 6 – G, H). Depending on the dysplasia degree, it may be classified as low, intermediate and high risk of malignancy [38], so that severity of the dysplasia is the key standard in malignancy prediction [39]. However, diagnosis of dysplasia is rather subjective and as such it is highly dependent on the pathologist/researcher [38, 39]. Another controversial issue is that it is virtually impossible to accurately predict which lesion, even among those with dysplasia, will develop into a malignant one [39]. Rather, we might get to know which lesion is more likely to become

Oral HPV Related Diseases: A Review and an Update 29

malignant, if clinic and histological characteristics are analyzed in association [38.37]

of malignant lesions in imunossupressed patients [38]

carcinoma, OLP and secondary syphilis.

lesions may relapse in the long run [38, 42]

and it has low probability of metastasis [43, 44].

**5.7. Oral verrucous carcinoma**

Viral etiology is unclear. Although HPV 6, 11 and 16 have been predominantly found, and also HPV 18, 31, 33, 35 [18, 38] in lesions, the viral etiology remains controversial. It seems that lesions which contain HPV are less malignant than oral leukoplakia in smokers, similar to what happens in OSCC. HPV-16 is present in 80% of the lesions, regardless of malignancy [5], and it has already been established that type 16 is related to OSCC in nonsmoker or nondrinkers. EBV seems to be an etiologic factor of oral leukoplakia because it appears in a great number

Differential diagnoses are leukoedema, white sponge nevus (*Cannon's disease*), contact dermatitis lesions, chronic biting, nicotinic stomatitis, OSCC, oral hairy leukoplakia, verrucous

There has not been any agreement as to the best treatment course, and prevention (smoking and drinking avoidance and a diet rich in fruits and vegetables) remains the best approach. A topical treatment based on topical bleomicyn and systemic retinoid is used as an effective short term treatment, however there are doubts as to its long term efficacy. Invasive treatments include cryosurgery, CO2 laser, and surgical resection. They are effective in the short run, but

Oral verrucous carcinoma (OVC) is a squamous cell carcinoma (SCC) subtype [15, 43, 44], but it shows a much more benign behavior, with well distinguished morphology and clinical presentation. It is located on the head, neck and genitals, and more notably on the oral mucosa,

OVC is a rare tumor and had been described by Ackerman [15, 43, 44] in 1948 as a cancer that involves the lips, oropharynx and laryngeal mucosa. It is also known as Ackerman's tumor. However, the condition has also been referred as florid oral papilomatosis, epithelioma cuniculatum, carcinoma cuniculatum and also as Buschke-Loewestein tumor [43]. Nowadays

The etiopathogenesis of OVC is unknown, but some studies have found associations mostly with smoking, some alcohol ingestion and infection by HPV [15, 44]. OVC related co-factors are poor oral hygiene, OLP or the presence of leukoplakia lesions. HPV may have an important

carcinoma cuniculatum is considered as a separated pathologic entity [45].

role in tumor development and progression, but further research is necessary [44].

Oral leukoplakia may be located on lip vermillion, gingival, tongue and floor of mouth, and it is on these latter regions that there is a higher risk of malignancy (around 43%) [38, 40]. Oral leukoplakia distribution may be local or disseminated [41] (Figure 6 – A, F).

**Figure 6.** OL: Oral leukoplakia. OL located at lateral (**A-B**) and ventral tongue show higher risk for malignant transfor‐ mation. These lesions may be homogenously white (**A**), or associated with ulcers (**B**). Other common location is gingi‐ va (**C-D**), floor of mouth (**E**) and alveolar ridge (**F**) and a traumatic cause or association with candidiasis should be ruled out before biopsy. Microscopically leukoplakia can demonstrate only epithelial hyperplasia with acanthosis and hyper‐ parakeratosis (**G**; HE, Objective 4x), without dysplasia (**H**; HE, Objective 20x). In this case inflammatory infiltrate was scarce. *Clinical images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

Histological examination reveals a range of epithelium changes varying from innocuous hyperplasia to dysplasia of varying degrees [18]. However, more commonly, OL presents hyperkeratosis and epithelial hyperplasia without dysplasia [38] (Figure 6 – G, H). Depending on the dysplasia degree, it may be classified as low, intermediate and high risk of malignancy [38], so that severity of the dysplasia is the key standard in malignancy prediction [39]. However, diagnosis of dysplasia is rather subjective and as such it is highly dependent on the pathologist/researcher [38, 39]. Another controversial issue is that it is virtually impossible to accurately predict which lesion, even among those with dysplasia, will develop into a malignant one [39]. Rather, we might get to know which lesion is more likely to become malignant, if clinic and histological characteristics are analyzed in association [38.37]

Viral etiology is unclear. Although HPV 6, 11 and 16 have been predominantly found, and also HPV 18, 31, 33, 35 [18, 38] in lesions, the viral etiology remains controversial. It seems that lesions which contain HPV are less malignant than oral leukoplakia in smokers, similar to what happens in OSCC. HPV-16 is present in 80% of the lesions, regardless of malignancy [5], and it has already been established that type 16 is related to OSCC in nonsmoker or nondrinkers. EBV seems to be an etiologic factor of oral leukoplakia because it appears in a great number of malignant lesions in imunossupressed patients [38]

Differential diagnoses are leukoedema, white sponge nevus (*Cannon's disease*), contact dermatitis lesions, chronic biting, nicotinic stomatitis, OSCC, oral hairy leukoplakia, verrucous carcinoma, OLP and secondary syphilis.

There has not been any agreement as to the best treatment course, and prevention (smoking and drinking avoidance and a diet rich in fruits and vegetables) remains the best approach. A topical treatment based on topical bleomicyn and systemic retinoid is used as an effective short term treatment, however there are doubts as to its long term efficacy. Invasive treatments include cryosurgery, CO2 laser, and surgical resection. They are effective in the short run, but lesions may relapse in the long run [38, 42]

### **5.7. Oral verrucous carcinoma**

rarely affects immunocompetent people and it does not need a specific treatment [40].

Oral leukoplakia may be located on lip vermillion, gingival, tongue and floor of mouth, and it is on these latter regions that there is a higher risk of malignancy (around 43%) [38, 40]. Oral

**Figure 6.** OL: Oral leukoplakia. OL located at lateral (**A-B**) and ventral tongue show higher risk for malignant transfor‐ mation. These lesions may be homogenously white (**A**), or associated with ulcers (**B**). Other common location is gingi‐ va (**C-D**), floor of mouth (**E**) and alveolar ridge (**F**) and a traumatic cause or association with candidiasis should be ruled out before biopsy. Microscopically leukoplakia can demonstrate only epithelial hyperplasia with acanthosis and hyper‐ parakeratosis (**G**; HE, Objective 4x), without dysplasia (**H**; HE, Objective 20x). In this case inflammatory infiltrate was scarce. *Clinical images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército*

*(OCEx).*

Treatment should address the underlying cause of immunosuppression.

28 Trends in Infectious Diseases

leukoplakia distribution may be local or disseminated [41] (Figure 6 – A, F).

Oral verrucous carcinoma (OVC) is a squamous cell carcinoma (SCC) subtype [15, 43, 44], but it shows a much more benign behavior, with well distinguished morphology and clinical presentation. It is located on the head, neck and genitals, and more notably on the oral mucosa, and it has low probability of metastasis [43, 44].

OVC is a rare tumor and had been described by Ackerman [15, 43, 44] in 1948 as a cancer that involves the lips, oropharynx and laryngeal mucosa. It is also known as Ackerman's tumor. However, the condition has also been referred as florid oral papilomatosis, epithelioma cuniculatum, carcinoma cuniculatum and also as Buschke-Loewestein tumor [43]. Nowadays carcinoma cuniculatum is considered as a separated pathologic entity [45].

The etiopathogenesis of OVC is unknown, but some studies have found associations mostly with smoking, some alcohol ingestion and infection by HPV [15, 44]. OVC related co-factors are poor oral hygiene, OLP or the presence of leukoplakia lesions. HPV may have an important role in tumor development and progression, but further research is necessary [44].

HPV has been widely described as one of the causes of OVC, and the most commonly found types are 6, 11, 16 and 18, which were identified by polymerase chain reaction (PCR), restriction fragments analyses and DNA slot hybridization [44].

Main OVC differential diagnosis is verrucous hyperplasia, which is very similar, clinically and histologicallly. Verrucous hyperplasia has in fact been regarded as an OVC precursor [43]. Other differential diagnoses are OLP, benign keratosis, chronic candidiasis, verruca vulgaris, oral leukoplakia, reactive keratosis epithelial hyperplasia, pseudoepitheliomatous hyperpla‐ sia. It is difficult to distinguish OSCC from OVC, because they may share a similar clinical

Oral HPV Related Diseases: A Review and an Update 31

Besides that, tumors mainly composed of OVC may contain small areas of OSCC and behave as one. Ideally, for definitive diagnosis the entire tumor mass with its surrounding tissue

The treatment main option is surgical resection [15, 46] that may be associated with radiother‐ apy particularly on larger lesions. Relapse rate is high when surgical resection or radiotherapy is performed in isolation. Prognosis of OVC is better than for other types of tumor. Cytostatic drugs, such as α- interferon (IFN), should be considered for patients who cannot undergo

OSCC is a worldwide problem [47], representing approximately 3% of all malignant neo‐ plasms; which means more than five thousand diagnosed cases a day [48], and more than 90%

It is a condition primarily related to environmental factors [8] and lifestyle as heavy smoking (more than a pack a day) and drinking (more than 100g a day) [47]. These two are the main risk factors for malignant epithelial transformation. Other risk factors include compromised immune system, poor buccal hygiene and inadequate eating habits [47, 49]. However, OSCC

Friedrich et al. reported a 20% to 30% HPV association with OSCC [50]. A meta-analysis indicates that oral infection with HPV is an independent risk factor for OSCC. [51] Typically, elderly people [47, 49] are more affected than young people. However, the incidence in young adults is increasing. Some studies have shown that OSCC in young adults follow a different clinical course, being more aggressive and affecting more males [47]. On the other side, other authors have shown no difference in survival among elderly and young adults with OSCC [52].

The most commonly affected site for OSCC is the tongue, especially on inferior and lateral surfaces (40%) [53](Figure 8 – A, F), but it can also affect buccal mucosa, lips, posterior

The clinical picture may vary among OSCC types. Typically they are nodular or ulcerative lesions [15, 18], with exophytic or ulceroproliferative features [47]. At more advanced stages lesions present an ulcerated center, not well defined with hard borders. At this point, symp‐ toms such as loss of teeth, bleeding, dysarthria, dysphagia, odynophagia and otalgy may develop [54].Some of them, for unknown reasons, do not progress into metastasis, while others infiltrate quickly, invading the lymph nodes [55]. Tongue and floor of the mouth tumors invade cervical lymph nodes in up to 25% of initial stage cases [56, 57] and are often submitted to

picture and incisional biopsy excerpts may not contain atypias [44].

surgery, but results are not superior from those obtained with surgery [46].

may affect 15 to 20% of patients with no known risk for the condition [8].

mandibular ridge, gingiva, hard palate and retromolar trigone [47, 49, 53, 54].

should be excised and sent for histopathologic analysis [43].

**5.8. Oral Squamous Cell Carcinoma (OSCC)**

of all oral cancers [49].

Oral verrucous carcinoma is a male disease and affects predominantly the 50-80 age group [44]. OVC is characteristically situated on the oral mucosa, gingiva, mandible alveolus crest, tongue and lips [44].

It appears with slow exophytic growth, resulting in verrucous cauliflower lesions, with white plaques, normally extensive and with well demarcated hyperkeratotic lesions [15, 43, 44]. It is well circumscribed, invasive only on surface, with low probability of metastasis [43] (Fig‐ ure7 – A, C). People usually look for doctors because of the extensive rapid growth, which scares them.

OVC histology is characterized by the presence of acanthosis and keratinization with keratin plugging and clefting [43, 44]. They are irregular and may extend into cleft. Atypia is minimal and usually there is inflammatory infiltrate on the subepthelial layer around epithelial invaginations which seem to compress the underlying tissue ("elephant feet") [44] (Figure 7 – D, E).

**Figure 7.** Oral verrucous carcinoma of the lip mucosa. Typical clinical presentation showing an indolor sessile nodule with a white verrucous surface (**A,B**). Surgical excision was performed resulting in an excellent esthetic and functional outcome (**C**). Microscopically, evident hyperkeratosis is observed, with epithelial acanthosis and invasion as pushing borders towards the stroma (**D**). Minimal epithelial atypia is seen along with a strong lymphocytic infiltrate (**E**). *Images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

Main OVC differential diagnosis is verrucous hyperplasia, which is very similar, clinically and histologicallly. Verrucous hyperplasia has in fact been regarded as an OVC precursor [43]. Other differential diagnoses are OLP, benign keratosis, chronic candidiasis, verruca vulgaris, oral leukoplakia, reactive keratosis epithelial hyperplasia, pseudoepitheliomatous hyperpla‐ sia. It is difficult to distinguish OSCC from OVC, because they may share a similar clinical picture and incisional biopsy excerpts may not contain atypias [44].

Besides that, tumors mainly composed of OVC may contain small areas of OSCC and behave as one. Ideally, for definitive diagnosis the entire tumor mass with its surrounding tissue should be excised and sent for histopathologic analysis [43].

The treatment main option is surgical resection [15, 46] that may be associated with radiother‐ apy particularly on larger lesions. Relapse rate is high when surgical resection or radiotherapy is performed in isolation. Prognosis of OVC is better than for other types of tumor. Cytostatic drugs, such as α- interferon (IFN), should be considered for patients who cannot undergo surgery, but results are not superior from those obtained with surgery [46].

### **5.8. Oral Squamous Cell Carcinoma (OSCC)**

HPV has been widely described as one of the causes of OVC, and the most commonly found types are 6, 11, 16 and 18, which were identified by polymerase chain reaction (PCR), restriction

Oral verrucous carcinoma is a male disease and affects predominantly the 50-80 age group [44]. OVC is characteristically situated on the oral mucosa, gingiva, mandible alveolus crest, tongue

It appears with slow exophytic growth, resulting in verrucous cauliflower lesions, with white plaques, normally extensive and with well demarcated hyperkeratotic lesions [15, 43, 44]. It is well circumscribed, invasive only on surface, with low probability of metastasis [43] (Fig‐ ure7 – A, C). People usually look for doctors because of the extensive rapid growth, which

OVC histology is characterized by the presence of acanthosis and keratinization with keratin plugging and clefting [43, 44]. They are irregular and may extend into cleft. Atypia is minimal and usually there is inflammatory infiltrate on the subepthelial layer around epithelial invaginations which seem to compress the underlying tissue ("elephant feet") [44]

**Figure 7.** Oral verrucous carcinoma of the lip mucosa. Typical clinical presentation showing an indolor sessile nodule with a white verrucous surface (**A,B**). Surgical excision was performed resulting in an excellent esthetic and functional outcome (**C**). Microscopically, evident hyperkeratosis is observed, with epithelial acanthosis and invasion as pushing borders towards the stroma (**D**). Minimal epithelial atypia is seen along with a strong lymphocytic infiltrate (**E**). *Images*

*obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

fragments analyses and DNA slot hybridization [44].

and lips [44].

30 Trends in Infectious Diseases

scares them.

(Figure 7 – D, E).

OSCC is a worldwide problem [47], representing approximately 3% of all malignant neo‐ plasms; which means more than five thousand diagnosed cases a day [48], and more than 90% of all oral cancers [49].

It is a condition primarily related to environmental factors [8] and lifestyle as heavy smoking (more than a pack a day) and drinking (more than 100g a day) [47]. These two are the main risk factors for malignant epithelial transformation. Other risk factors include compromised immune system, poor buccal hygiene and inadequate eating habits [47, 49]. However, OSCC may affect 15 to 20% of patients with no known risk for the condition [8].

Friedrich et al. reported a 20% to 30% HPV association with OSCC [50]. A meta-analysis indicates that oral infection with HPV is an independent risk factor for OSCC. [51] Typically, elderly people [47, 49] are more affected than young people. However, the incidence in young adults is increasing. Some studies have shown that OSCC in young adults follow a different clinical course, being more aggressive and affecting more males [47]. On the other side, other authors have shown no difference in survival among elderly and young adults with OSCC [52].

The most commonly affected site for OSCC is the tongue, especially on inferior and lateral surfaces (40%) [53](Figure 8 – A, F), but it can also affect buccal mucosa, lips, posterior mandibular ridge, gingiva, hard palate and retromolar trigone [47, 49, 53, 54].

The clinical picture may vary among OSCC types. Typically they are nodular or ulcerative lesions [15, 18], with exophytic or ulceroproliferative features [47]. At more advanced stages lesions present an ulcerated center, not well defined with hard borders. At this point, symp‐ toms such as loss of teeth, bleeding, dysarthria, dysphagia, odynophagia and otalgy may develop [54].Some of them, for unknown reasons, do not progress into metastasis, while others infiltrate quickly, invading the lymph nodes [55]. Tongue and floor of the mouth tumors invade cervical lymph nodes in up to 25% of initial stage cases [56, 57] and are often submitted to elective neck dissection. Cervical metastasis at diagnosis is the main indicator of a bad prognosis [45].

Histologically a range of features may be present, but it is important to detect epithelial invasion in the stroma, that may occur as islands, cords, sheets and isolated epithelial malig‐ nant cells. Keratin may be present, mostly in well and moderately differentiated tumors. There are varying degrees of atypia, nuclear and cellular pleomorphism with aberrant and regular mitosis (Figure 9 – A, D). Usually poorly differentiated tumors are related to recurrence [58]. Clinic and histological features are important to determine treatment, prognostic factors and survival rates [58, 59]. There is a TNM staging scheme, for OSCC and salivary gland tumors [60]. At the initial stages survival rates reach 80%, while at more advanced stages they decrease

Oral HPV Related Diseases: A Review and an Update 33

**Figure 9.** OSCC histopathology. It is possible to observe superficial non affected oral epithelia and tumoral islands in the stroma (**A**; HE, Objective 4x). A closer view of the tumoral islands with central keratin (**B**; HE, Objective 10x). Pleo‐ morphism and atypia are observed (**C**; HE, Objective 10x), as well as mitosis (\*) and intercellular bridges (**D**; HE, Objec‐

A correlation between HPV and cervical SCC of the utherus has been identified, but despite the strong evidence of HPV presence, there is no clear-cut proof that would point to HPV as

to 21% [54].

tive 20x).

**Figure 8.** Clinical aspect of OSCC. It may present as an exophityc nodule, ulcerated (**A-B**) or not (**C**). It can also be de‐ tected as a small induration interspersed in a white plaque (**D** - arrow). It may show intra osseous invasion (**E**), with a strong white component, and reach distant sites (**F**) from the initial spot. *Images obtained from the archives of the Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

Histologically a range of features may be present, but it is important to detect epithelial invasion in the stroma, that may occur as islands, cords, sheets and isolated epithelial malig‐ nant cells. Keratin may be present, mostly in well and moderately differentiated tumors. There are varying degrees of atypia, nuclear and cellular pleomorphism with aberrant and regular mitosis (Figure 9 – A, D). Usually poorly differentiated tumors are related to recurrence [58]. Clinic and histological features are important to determine treatment, prognostic factors and survival rates [58, 59]. There is a TNM staging scheme, for OSCC and salivary gland tumors [60]. At the initial stages survival rates reach 80%, while at more advanced stages they decrease to 21% [54].

elective neck dissection. Cervical metastasis at diagnosis is the main indicator of a bad

**Figure 8.** Clinical aspect of OSCC. It may present as an exophityc nodule, ulcerated (**A-B**) or not (**C**). It can also be de‐ tected as a small induration interspersed in a white plaque (**D** - arrow). It may show intra osseous invasion (**E**), with a strong white component, and reach distant sites (**F**) from the initial spot. *Images obtained from the archives of the*

*Stomatology Specialization at Odontoclínica Central do Exército (OCEx).*

prognosis [45].

32 Trends in Infectious Diseases

**Figure 9.** OSCC histopathology. It is possible to observe superficial non affected oral epithelia and tumoral islands in the stroma (**A**; HE, Objective 4x). A closer view of the tumoral islands with central keratin (**B**; HE, Objective 10x). Pleo‐ morphism and atypia are observed (**C**; HE, Objective 10x), as well as mitosis (\*) and intercellular bridges (**D**; HE, Objec‐ tive 20x).

A correlation between HPV and cervical SCC of the utherus has been identified, but despite the strong evidence of HPV presence, there is no clear-cut proof that would point to HPV as an isolate SCC cause on oral cavity. Some studies argue that HPV is a mere supporting causer [1, 61] while another study indicates that tumors positive for oncogenic types of HPV may show better survival [62], mainly in oropharynx, where HPV positive tumors are associated with a specific morphology (basaloid squamous cell carcinoma, a subtype of conventional carcinoma) and positivity for p16 using immunohistochemistry [63].

proteins. However, the mechanisms behind immune response against high risk HPV remain

Oral HPV Related Diseases: A Review and an Update 35

The identification of various types of HPV is a recent technological advance due to the growth

Diagnoses methods vary from simple to sophisticated ones, ranging from light microscopy to DNA expression, with low to high sensitivity. Light microscopy and in situ hybridization are considered low sensitivity methods because it only tests positive when there are more than 10 viral DNA copies per cell. Among the intermediate sensitivity methods we find southern blot, do blot and reverse hybridization with a positive detection result when there is from 1 to 10 DNA copies per cell. High sensitivity methods, such as PCR, needs less than 1 viral DNA copy

This method provides some data, even though it has low sensibility and it does not inform the HPV type. The most common HPV induced changes are epithelial thickening, prominent keratohyalin granules, hyperkeratosis, nuclear dysplasia, hyperchromasia, double nucleation of superficial and intermediated cell, perinuclear cytoplasmic halos, and atypical immature

HPV particles may be identified by electron microscopy (EM), but not the HPV type. EM can detect the presence of virion on koilocytic and dyskeratotic cell nuclei, but it is a limited method to investigate infection, because high risk HPV do not reproduce and as such cannot be

Molecular methods can be divided into two types: non-hybridization, such as in situ amplifi‐ cation, southern and dot blot hybridization and the amplified, such as target amplification, signal amplification and probe amplification. Target amplification is best exemplified by PCR. Signal amplification may be represented by hybrid technique sample. Probe amplification which is a compound-probe is added to a probe generating signal (Ligase Chain Reaction)

*In situ* hybridization using biotinylated probes is a common method for detecting HPV in oral epithelium. It is practical and economical for screening for HPV in clinical pathology labora‐

unclear [67-69].

**7. HPV detection methods**

impossibility in tissue cultures and research animals.

per cell for microorganism detection [70].

**7.1. Light microscopy**

**7.2. Electron microscopy**

identified through EM [5].

**7.3. Molecular methods**

according to literature [5].

**7.4.** *In Situ* **Hybridization (ISH)**

metaplasia [9].

HPV-16 has been found in 90% of head and neck cancers and in 50% of oropharynx [1, 18, 53, 64]. However, some authors have not found such association [64].

Potentially malignant disorders such as leukoplakia, erytroplakia, proliferative verrucous leukoplakia and lichen planus may progress to OSCC [1] and upon biopsy, there may be already areas of an actual OSCC [65].

Surgical resection is the treatment of choice when the lesion is placed on oral cavity while chemoradiotherapy is used when the oropharynx is the afflicted site [22] or if it is a tumor in a very advanced stage [66].

Surgery may impair some functions as speech, swallowing, and chewing and abruptly change quality of life. To maintain swallowing and speech, an alternative course is ablative surgery (microvascular free tissue), but this is not regarded to be as effective as surgical resection. In advanced stage when metastasis is located on upper aerodigestive tract, treatment should be multimodal, combining surgery and chemoradiotherapy [46].

Recurrent OSCC is challenging as the risk of complication is increased due to fibrosis and tissue hipovascularization [51].

Radiotherapy may be primary, adjuvant or neoadjuvant. It is regarded as primary for unre‐ sectable tumor or for patients who cannot undergo surgery, adjuvant as a post-surgery complementary method, and neoadjuvant when performed before surgery to facilitate tumor resection [54].


**3. Implementing QoS strategies**

Quality of Service requirements in the Internet lead to the development of several approaches for realizing QoS guarantees. The best known approaches are DiffServ [26] and IntServ [27]. While these protocols can be used in the global Internet, they can hardly be applied in the context of sensor networks due to multiple reasons. Sensor networks which consist of small and resource-constrained devices cannot run resource-intensive protocols that have high requirements concerning computational power, memory and bandwidth. Moreover, unreliable links and time varying channel conditions make QoS in WSNs a difficult task [28].

Instead, light-weight protocols, which require little synchronization between the nodes involved in the communication, are more suitable in this context. In order to build such light-weight protocols, simple QoS strategies need to be employed. These strategies, which can be implemented using preamble sampling protocols, should on the one hand be as simple as possible while fulfilling the requirements of a large number of applications on the other hand. In Subsection 3.1, we will discuss a number of strategies that should be implemented by a QoS approach. Afterwards, we will highlight how such an approach needs to be configured to provide the QoS strategies in Subsection 3.2. The impact of preamble transmission in multi-hop wireless networks is discussed in Subsection 3.3 by comparing the performance of the BPS-MAC protocol and Zigbee in a WSNs with high node density.