desmoplastic fibroma ( df ) , a benign locally aggressive lesion of the bone is recognized as an intra - osseous counterpart of soft tissue fibromatosis and is usually seen affecting the long bones , pelvis and only occasionally presents itself as a jaw lesion .
mandible is most commonly affected when compared to the maxilla and the cranium in the head and neck region . a systematic literature search of the pubmed database of national library of medicine using  df  and  mandible  as keywords revealed a total of 57 published cases occurring in the mandible alone from the year 19692014 .
the cause for df is unknown and is stipulated to have a varied pathogenesis ranging from genetic , endocrine and traumatic factors to an exuberant reactive proliferation .
when differentiating it from other neoplasms that behave aggressively , a history of expansion or perforation of the cortical plates along with the histopathological confirmation would be a pointer in the right direction .
a 35-year - old female patient visited the department of oral medicine and radiology , with the chief complaint of slowly growing painless swelling in the left lower back tooth region since 3 years [ figure 1 ] .
clinical extra - oral examination revealed expansion of the left inferior border of the mandible and intra - oral examination revealed a solitary bony hard swelling measuring about 4.0 cm  5.0 cm in size with obliteration of the left buccal vestibule in relation to 37 and 38 [ figure 2 ] .
clinical image showing swelling of left side of lower jaw intra - oral photograph showing obliteration of the left buccal vestibule in relation to 37 , 38 a left lateral oblique view of radiograph showed multilocular radiolucencies with fine trabeculations leading to a soap bubble appearance extending from the left angle of the mandible to the mesial root of the mandibular left first molar .
no displacement of teeth or resorption of the root was seen [ figure 3 ] . left lateral oblique view of radiograph showing multilocular radiolucencies a computerized tomography ( ct ) scan demonstrated buccal and lingual cortical plate expansion and a soap bubble appearance [ figure 4 ] . computed tomography scan showing buccal and lingual cortical plate expansion surgical excision of the lesion
the hematoxylin and eosin stained tissue section showed hypo and hyper - cellular areas with proliferation of plump fibroblasts arranged in interlacing fascicles and dense collagen .
focal areas of the section also revealed dense collagenous stroma with foci of hyalinization [ figure 8 ] .
photomicrograph showing hypo - cellular and hyper - cellular areas with spindle cells arranged in interlacing fascicles ( h&e stain , 10 ) photomicrograph showing hyper - cellular area with proliferating plump fibroblasts , ( h&e stain , 20 ) photomicrograph showing proliferating plump , spindle - shaped fibroblasts in a collagenous stroma ( h&e stain , 40 ) photomicrograph showing a focus of dense collagenous stroma with focal areas of hyalinization ( h&e stain , 10 ) a final diagnosis of df was arrived at after histopathological examination .
df is a rare , locally aggressive myofibroblastic benign tumor of connective tissue origin . as an intra - osseous lesion
df was first described by jaffe in 1958 and named as df . in 1965 ,
the first report about a df of the jaw was presented by griffith und irby .
the histologic criteria for df as defined by the world health organization is  a rare benign bone tumor composed of spindle - shaped cells with minimal cytological atypia and abundant collagen production .
 desmoid tumor also called as  aggressive fibromatosis ,  was described before df .
about 69% of desmoid tumors are abdominal ; the extra - abdominal variety occurring in the bone is the df .
although df can affect any age group , most patients are affected in the first three decades of life . in our case ,
the average age of patients at the time of the final diagnosis is 15.1 years .
metaphysis of long bones especially tibia , scapula and femur are the most frequent sites of involvement .
mandible is the fourth most common site of involvement and sex predilection remains unclear . in the mandible , the lesions tend to occur posteriorly at the ramus - angle region .
this is similar to our case report , where the lesional tissue is in relation to the second and third molars .
the symptoms are nonspecific including diffuse , moderate pain in the region of the tumor , both at rest and on movement or when bone bears any weight . in the maxillofacial region ,
dfs usually are painless , slow - growing firm masses . a similar history of a painless
radiographic appearance may vary from uni - locular to multi - locular , with or without expansion or perforation of cortical plates according to frick et al .
radiographs showed osteolytic lesions with coarsened ridge - like trabeculae in 63% of cases , osteolytic lesions in 24% of cases and mixed lytic and mildly sclerotic lesions in 13% cases .
ct revealed radiolucent ( 65% ) or mixed radiolucent and mildly sclerotic ( 35% ) matrix patterns .
the ct in our case clearly showed cortical expansion without any resorption or displacement of adjacent teeth .
t1-weighted sequences in mri showed that the signal intensities within the lesions were isointense or hypointense to adjacent normal muscle .
the hypocellular areas of the tumors with abundant collagen are responsible for the areas of t2-shortening while hyper - cellular parts filled with fibroblasts or necrotic areas are responsible for the higher intensity parts within the lesions . on gross examination
, the desmoid tumor appears as firm , rubbery , white , nonencapsulated fibrous growth .
histologically , the df contains mature fibrous connective tissue , low to variable cellularity and spindle - shaped fibroblasts / myofibroblasts with uniform long nuclei in an abundant stroma of collagenous matrix lacking cellular pleomorphism , nuclear hyperchromatism or mitoses .
the differential diagnosis to be considered histologically would be spindle cell tumors of which low - grade fibrosarcoma is the most important .
tumors such as fibrous histiocytoma , fibrous dysplasia , or a low - grade intra - osseous osteosarcoma ; tumor - like lesions such as aneurysmal bone cyst and the juvenile bone cyst can also present with a similar clinical picture . though fibrosarcoma exhibits a highly cellular stroma along with high grades of polymorphism and mitosis , the low - grade variant shows a collagen rich tissue with low cell count and no mitotic activity .
this is very similar to the histopathological picture of the df and a definitive diagnosis is possible only with postoperative clinical development .
found that df has no immunoreactivity of cd117 , estrogen and progesterone receptors ; and 50% cases showed positivity for muscle - specific markers and the -catenin pathway does not seem to have the same essential role in the tumorigenesis of df , as it has in desmoid type fibromatosis .
found that the majority of the tumor cells express the mesenchymal marker vimentin and no immunoreactivity for antidesmin and anti - s-100 protein .
df of maxilla or mandible with extra - osseous extensions is treated with complete excision including a margin of uninvolved soft tissue .
the recurrence rate of about 40 - 47% is seen in lesions treated by curettage or intra - lesional resection making follow - up a necessity .
 desmoplastic fibroma ( df ) is a benign intra - osseous neoplasm , that is , recognized as the intra - osseous counterpart of soft tissue fibromatosis in both gnathic and extra - gnathic sites . 
 it has a propensity for locally aggressive behavior and local recurrence . 
 an occurrence of intra - osseous lesion other than that of odontogenic origin is rare in the jaws . in this case report , we define the clinico - pathological and radiographic features of df of the mandible in a 35-year - old female , who presented to the outpatient department with a 3-year history of a slowly expanding painless mass in the left mandibular posterior region . 
 thus , we present a classic case of df exhibiting characteristic features along with a review of the literature . 
INTRODUCTION
CASE REPORT
DISCUSSION
Financial support and sponsorship
Conflicts of interest