melanoacanthoma is a benign and uncommon pigmented mucocutaneous lesion characterized by dendritic melanocytes dispersed throughout the epithelium .
published the first retrospective review of 10 cases of oral melanoacanthoma reported in the literature in 1983 .
oral melanoacanthoma usually occurs on the buccal mucosa ( 51.4% ) , with fewer lesions originating on the palate ( 22.2% ) , lips ( 15.2% ) and gingiva ( 5.6% ) .
oral melanoacanthoma is seen almost exclusively in blacks , shows a female predilection and is most common during the third and fourth decade of life . the lesion is smooth , flat or slightly raised , dark brown to black in color . lesions often demonstrate a rapid increase in size and they occasionally reach a diameter of several centimeters within a period of few week , potentially masquerading as a melanoma . to the best of our ability
, a comprehensive review of literature on gingival melanoacanthoma revealed 12 cases mostly involving singular lesions [ table 1 ] .
herein , we present an unusual case report of gingival melanoacanthoma , which presented clinically as pigmented unilateral gingival enlargement . reported cases of gingival melanoacanthomas
a 13-year - old male patient attended the department of periodontics , mahatma gandhi post graduate institute of dental sciences , pondicherry , in may 2011 for gingival enlargement and difficulty in mastication .
he first noticed enlargement 6 months earlier along the buccal aspect of tooth 26 , which increased in size slowly to the present clinical picture .
the clinical examination was significant for the presence of pigmented diffuse gingival enlargement along buccal and palatal aspects of 24 , 25 , 26 , 27 and lingual aspects of teeth 34 , 35 , 36 , 37 [ figure 1 ] .
gingival enlargement was extending up to middle third of the crown of tooth 24 , partially covering the occlusal surface of teeth 25 , 26 and completely covering the tooth 27 [ figure 2 ] and extending up to occlusal surface of teeth 34 , 35 , 36 , 37 .
the gingival enlargement was firm in consistency , painless , brownish black in color with well - defined borders and there was no associated erythematous background .
melanoacanthoma on the maxillary posterior gingiva melanoacanthoma on the occlusal surface of 26 , 27 other significant dental findings included root canal treated fractured tooth 21 and congenitally missing tooth 23 .
based on the clinical findings , provisional diagnosis of idiopathic gingival enlargement was made and gingivectomy was planned for the treatment .
patients parents provided oral consent for treatment prior to the initial and additional tests and the dental treatment that followed .
gingivectomy was performed under local anesthesia on the buccal aspect of ii quadrant [ figure 3 ] and the excised tissue was sent for biopsy [ figure 4 ] .
one week later , gingivectomy was performed on the palatal aspect of ii quadrant followed by lingual aspect of iii quadrant after 1 week .
patient experienced an uneventful post - operative recovery [ figure 5 ] at 1 year recall examination there was no recurrence of gingival enlargement at the surgical sites [ figure 6 ] .
patient will continue to be monitored on a 6 month basis and any new gingival enlargement / lesion will undergo histopathologic investigation .
gingivectomy carried out in ii quadrant  buccal aspect excised tissue after gingivectomy surgical area 2 weeks post - operatively one year follow - up with no recurrence histopathological examination revealed numerous dendritic melanocytes distributed in basal and suprabasal layers of acanthotic epithelium .
there was no spillage of melanin pigment / melanocytes in subepithelial zone [ figure 8 ] .
microscopical features of melanoacathoma showing dendritic melanocytes distributed throughout acanthotic epithelium ( h and e ; original magnification 100 ) melanoacanthoma showing dendritic melanocytes distributed in basal and suprabasal layers of epithelium with normal connective tissue ( original magnification 45 )
a 13-year - old male patient attended the department of periodontics , mahatma gandhi post graduate institute of dental sciences , pondicherry , in may 2011 for gingival enlargement and difficulty in mastication .
he first noticed enlargement 6 months earlier along the buccal aspect of tooth 26 , which increased in size slowly to the present clinical picture .
the clinical examination was significant for the presence of pigmented diffuse gingival enlargement along buccal and palatal aspects of 24 , 25 , 26 , 27 and lingual aspects of teeth 34 , 35 , 36 , 37 [ figure 1 ] .
gingival enlargement was extending up to middle third of the crown of tooth 24 , partially covering the occlusal surface of teeth 25 , 26 and completely covering the tooth 27 [ figure 2 ] and extending up to occlusal surface of teeth 34 , 35 , 36 , 37 .
the gingival enlargement was firm in consistency , painless , brownish black in color with well - defined borders and there was no associated erythematous background .
melanoacanthoma on the maxillary posterior gingiva melanoacanthoma on the occlusal surface of 26 , 27 other significant dental findings included root canal treated fractured tooth 21 and congenitally missing tooth 23 .
based on the clinical findings , provisional diagnosis of idiopathic gingival enlargement was made and gingivectomy was planned for the treatment .
patients parents provided oral consent for treatment prior to the initial and additional tests and the dental treatment that followed .
gingivectomy was performed under local anesthesia on the buccal aspect of ii quadrant [ figure 3 ] and the excised tissue was sent for biopsy [ figure 4 ] .
one week later , gingivectomy was performed on the palatal aspect of ii quadrant followed by lingual aspect of iii quadrant after 1 week .
patient experienced an uneventful post - operative recovery [ figure 5 ] at 1 year recall examination there was no recurrence of gingival enlargement at the surgical sites [ figure 6 ] .
patient will continue to be monitored on a 6 month basis and any new gingival enlargement / lesion will undergo histopathologic investigation .
gingivectomy carried out in ii quadrant  buccal aspect excised tissue after gingivectomy surgical area 2 weeks post - operatively one year follow - up with no recurrence
histopathological examination revealed numerous dendritic melanocytes distributed in basal and suprabasal layers of acanthotic epithelium .
there was no spillage of melanin pigment / melanocytes in subepithelial zone [ figure 8 ] .
microscopical features of melanoacathoma showing dendritic melanocytes distributed throughout acanthotic epithelium ( h and e ; original magnification 100 ) melanoacanthoma showing dendritic melanocytes distributed in basal and suprabasal layers of epithelium with normal connective tissue ( original magnification 45 )
oral melanoacanthoma is a benign reactive process and shows a rapid increase in size that reaches several centimeters within a few weeks .
the reported age of presentation ranges from 6 to 77 years with a mean age of 29 years .
though the lesion is most predominantly observed among black patients , occurrences have also been observed among caucasians , hispanics and asians .
the lesion usually occur on the buccal mucosa , but involvement of other sites such as the mucosa of lip , palate , gingiva and alveolar mucosa has also been reported .
the lesions are usually solitary and well - circumscribed , though a few authors have reported bilateral or multiple melanoacanthoma . with
the addition of featured case 13 patients with gingival melanoacanthoma have been reported [ table 1 ] . to the best of our knowledge ,
this is the first comprehensive case of gingival melanoacanthoma presented clinically as pigmented diffuse gingival enlargement . at 1 year follow - up examination of
the pathogenesis of oral melanoacanthomas is not yet clear , although these lesions are considered a reactive phenomenon .
there may be an idiosyncratic predisposition toward the formation of oral melanoacanthoma in the patient .
histopathological examination did not reveal nuclear pleomorphism , hyperchromatism and nests of melanocytes , suggestive of malignancy .
there was normal connective tissue with no spillage of melanin pigment / melanocytes in subepithelial zone . in the light of the history , clinical features and the histopathologic examination , the final diagnosis of oral melanoacanthoma
the clinical differential diagnosis of localized brown to black gingival pigmentations include smoker 's melanosis , drug induced pigmentation , physiologic pigmentation , addison 's disease , melanotic macule , pigmented nevi , spitz nevus , post - inflammatory melanosis , hemochromatosis , oral melanoma , mccune - albright syndrome and peutz - jegher 's syndrome . in early stages ,
therefore , sudden onset of oral pigmentation of unknown etiology needs histopathologic assessment for lesional identity and to rule out the presence of oral melanoma .
the lesion may undergo spontaneous regression after incisional biopsy . the present case required surgical excision only as a treatment option since the clinical presentation was diffuse gingival enlargement interfering with normal mastication .
to the best of our knowledge , this is the first case of gingival melanoacanthoma in the indian sub - continent .
pigmented gingival lesions of unusual clinical presentation should undergo histopathologic examination for timely identification and to rule out malignancy .
our case report emphasizes the need for clinicians to include gingival melanoacanthoma in the differential diagnosis of multifocal diffuse pigmented gingival enlargement and surgical excision is only treatment modality for such unusual clinical presentation .
 gingival melanoacanthoma is a rare , benign pigmented lesion characterized clinically by sudden onset and rapid growth of a macular brown black lesion and histologically by acanthosis of superficial epithelium and proliferation of dendritic melanocytes . 
 this article reports a previously undescribed case of pigmented unilateral diffuse gingival enlargement , which on histopathological examination proved to be melanoacanthoma . 
 intraoral examination revealed pigmented unilateral diffuse gingival enlargement in relation to second and third quadrants buccally , palatally / lingually . 
 based on these clinical findings , gingivectomy was performed and the excised tissue was sent for biopsy . 
 microscopic examination revealed acanthotic and parakeratotic surface epithelium with dendritic melanocytes distributed in basal and suprabasal layers of the epithelium . 1 year follow - up recall revealed no recurrence of lesion at the surgical sites . 
 our patient exhibits an unusual clinical presentation of melanoacanthoma of gingiva . 
 pigmented gingival overgrowth of recent origin and without any etiologic factors warrants histopathologic examination . 
INTRODUCTION
CASE REPORT
Clinical findings
Treatment and follow-up
Histopathological findings
DISCUSSION
CONCLUSION