infiltrating lipomatosis of the face is a distinct clinicopathological rare entity which falls under the subgroup of lipomatous tumor like lesions and is characterized by collection of non - encapsulated , mature adipocytes that infiltrate local tissues , leading to craniofacial deformities and tend to recur after surgery . patients have normal psychomotor development with esthetics often being the primary concern . here , we report four cases of chronic infiltrating lipomatosis presenting in varying age groups with a history of recurrence in three cases . a 77-year - old male reported to the outpatient department , complaining of a swelling in the right cheek region since 30 years , with no history of pain or pus discharge . patient revealed a previous history of liposuction 7 years ago for the same complaint . on extraoral examination , a swelling was seen on the right cheek , extending from preauricular region to the lower border of the mandible , measuring approximately 8  10 cm in size [ figure 1a ] . ( a ) extent of the swelling extraorally ; ( b ) intraoral swelling covering the right buccal mucosa ; ( c ) gross specimen ; ( d ) adipocytes infiltrating neurovascular bundle ( h and e , 200 ) incisional biopsy was done which was suggestive of infiltrating lipomatosis , following which the patient underwent surgical removal of the lesion . excised tissue was submitted to the department of oral pathology as multiple soft tissue bits , with the largest bits measuring around 5  3 and 5  2 cm in size , brown and yellow in color , irregular in outline , and firm in consistency [ figure 1c ] . on microscopic examination , large amounts of adipose tissue composed of empty appearing adipocytes with peripherally placed nuclei were seen . numerous thick - walled arteries and nerve bundles were observed surrounded by adipose tissue [ figure 1d ] . a 17-year - old female reported with a complaint of swelling in the right cheek , present since birth . the lesional tissue was sent for histopathologic examination which was suggestive of an infiltrating lipomatous lesion . in late 2010 , she reported again in 2012 with an increase in the size of the previously reported swelling . on extraoral examination , a swelling was present unilaterally over the right maxilla / zygoma , extending upward till orbit , posteriorly till the ear lobe , and inferiorly to the lower border of the mandible [ figure 2a ] . intraorally , there was enlargement of the maxillary right posterior alveolar region , extending from the maxillary right second premolar posteriorly up to the tuberosity . on contrast - enhanced computed tomography ( cect ) , the right masseter and buccinator appeared heterogeneous with areas of fat attenuation within . there was an increase in the right side buccal fat with extraoral fat stranding which caused poor differentiation of lateral margins of underlying muscles [ figure 2b ] . right parotid and submandibular gland also appeared mildly bulky and heterogeneous with areas of fat attenuation within , likely due to fatty infiltration . an incisional biopsy was done , which on microscopic examination showed fat cells infiltrating in the muscle and admixed with blood vessels in a loosely collagenous stroma [ figure 2d ] . the patient underwent surgical excision and the excised tissue submitted to the department was in the form of multiple soft tissue bits , yellowish in color , the largest measuring 3  2.5  2 cm [ figure 2c ] . ( a ) extraoral extent ; ( b ) contrast - enhanced computed tomography showing fatty infiltration of the buccinator , masseter , and parotid gland ; ( c ) gross specimen ; ( d ) adipocytes infiltrating the muscle ( h and e , 200 ) a 20-year - old female presented with complaint of a swelling on the left side of the face , present since birth . there was a previous history of surgery at the age of 5 years for the same complaint . it was provisionally diagnosed as hemifacial hypertrophy as there was associated enlargement of the maxillary alveolus of the same side . on extraoral examination , a swelling was seen on the left side of the face , extending from preauricular region to the lower border of the mandible , measuring approximately 8  10 cm in size [ figure 3a ] . intraorally , there was enlargement of the left maxillary and mandibular alveolar processes , causing displacement of teeth [ figure 3b ] . ( a ) large swelling on the left side of the face ; ( b ) intraoral expansion of maxillary alveolar process ; ( c ) adipocytes infiltrating the marrow spaces ( h and e , 200 ) incisional biopsy was done and the gross specimen was received as two soft tissue bits measuring around 1.2  1  0.5 cm , 2  0.5  0.5 cm , irregular in outline , creamish brown in color , and soft in consistency . the hard tissue portion ( maxillary alveolus ) was received as three large - sized hard tissue bits measuring around 2  1.5  0.5 cm , 1.5  0.5  0.5 cm , and 0.8  0.5  0.5 cms , white and brown in color and hard in consistency . on microscopic examination , sections from upper lip and cheek of left side showed large amounts of adipose tissue infiltrating the muscle planes . decalcified sections from maxillary alveolus showed adipose tissue within the marrow spaces [ figure 3c ] . few resorbed and some normal bony trabeculae were also seen.incisional biopsy was suggestive of infiltrating lipomatosis.the patient is scheduled for an excisional surgery for esthetic purpose . a 5-year - old girl presented with the complaint of swelling on the left side of the face since birth with no history of pain or pus discharge . , there was a diffuse swelling over left cheek region , extending from infraorbital rim to lower border of mandible and anteroposteriorly from the angle of mouth to 2 cm in front of tragus [ figure 4a ] . intraoral examination revealed minor enlargement of alveolar process on the left side , early eruption of 23 , 24 , 26 , and early exfoliation of 63 and 64 . ( a ) diffuse swelling over left cheek ; ( b ) magnetic resonance imaging showing fatty infiltration magnetic resonance imaging ( mri ) showed poorly defined lipomatous lesion on the left side of the cheek , in subcutaneous plane , and buccal pad of fat , with secondary hypertrophy of maxillary alveolus and hyperplasia of left maxillary sinus . the received soft tissue specimen was measuring 1.5  0.8  0.4 cm in size , and was light brown in color , soft in consistency , and irregular in shape . the patient is being kept on a regular follow - up and no treatment has been advocated as the patient is very young . a 77-year - old male reported to the outpatient department , complaining of a swelling in the right cheek region since 30 years , with no history of pain or pus discharge . patient revealed a previous history of liposuction 7 years ago for the same complaint . on extraoral examination , a swelling was seen on the right cheek , extending from preauricular region to the lower border of the mandible , measuring approximately 8  10 cm in size [ figure 1a ] . ( a ) extent of the swelling extraorally ; ( b ) intraoral swelling covering the right buccal mucosa ; ( c ) gross specimen ; ( d ) adipocytes infiltrating neurovascular bundle ( h and e , 200 ) incisional biopsy was done which was suggestive of infiltrating lipomatosis , following which the patient underwent surgical removal of the lesion . excised tissue was submitted to the department of oral pathology as multiple soft tissue bits , with the largest bits measuring around 5  3 and 5  2 cm in size , brown and yellow in color , irregular in outline , and firm in consistency [ figure 1c ] . on microscopic examination , large amounts of adipose tissue composed of empty appearing adipocytes with peripherally placed nuclei were seen . numerous thick - walled arteries and nerve bundles were observed surrounded by adipose tissue [ figure 1d ] . a 17-year - old female reported with a complaint of swelling in the right cheek , present since birth . the lesional tissue was sent for histopathologic examination which was suggestive of an infiltrating lipomatous lesion . in late 2010 , she reported again in 2012 with an increase in the size of the previously reported swelling . on extraoral examination , a swelling was present unilaterally over the right maxilla / zygoma , extending upward till orbit , posteriorly till the ear lobe , and inferiorly to the lower border of the mandible [ figure 2a ] . intraorally , there was enlargement of the maxillary right posterior alveolar region , extending from the maxillary right second premolar posteriorly up to the tuberosity . on contrast - enhanced computed tomography ( cect ) , the right masseter and buccinator appeared heterogeneous with areas of fat attenuation within . there was an increase in the right side buccal fat with extraoral fat stranding which caused poor differentiation of lateral margins of underlying muscles [ figure 2b ] . right parotid and submandibular gland also appeared mildly bulky and heterogeneous with areas of fat attenuation within , likely due to fatty infiltration . an incisional biopsy was done , which on microscopic examination showed fat cells infiltrating in the muscle and admixed with blood vessels in a loosely collagenous stroma [ figure 2d ] . the patient underwent surgical excision and the excised tissue submitted to the department was in the form of multiple soft tissue bits , yellowish in color , the largest measuring 3  2.5  2 cm [ figure 2c ] . ( a ) extraoral extent ; ( b ) contrast - enhanced computed tomography showing fatty infiltration of the buccinator , masseter , and parotid gland ; ( c ) gross specimen ; ( d ) adipocytes infiltrating the muscle ( h and e , 200 ) a 20-year - old female presented with complaint of a swelling on the left side of the face , present since birth . there was a previous history of surgery at the age of 5 years for the same complaint . it was provisionally diagnosed as hemifacial hypertrophy as there was associated enlargement of the maxillary alveolus of the same side . on extraoral examination , a swelling was seen on the left side of the face , extending from preauricular region to the lower border of the mandible , measuring approximately 8  10 cm in size [ figure 3a ] . intraorally , there was enlargement of the left maxillary and mandibular alveolar processes , causing displacement of teeth [ figure 3b ] . ( a ) large swelling on the left side of the face ; ( b ) intraoral expansion of maxillary alveolar process ; ( c ) adipocytes infiltrating the marrow spaces ( h and e , 200 ) incisional biopsy was done and the gross specimen was received as two soft tissue bits measuring around 1.2  1  0.5 cm , 2  0.5  0.5 cm , irregular in outline , creamish brown in color , and soft in consistency . the hard tissue portion ( maxillary alveolus ) was received as three large - sized hard tissue bits measuring around 2  1.5  0.5 cm , 1.5  0.5  0.5 cm , and 0.8  0.5  0.5 cms , white and brown in color and hard in consistency . on microscopic examination , sections from upper lip and cheek of left side showed large amounts of adipose tissue infiltrating the muscle planes . decalcified sections from maxillary alveolus showed adipose tissue within the marrow spaces [ figure 3c ] . few resorbed and some normal bony trabeculae were also seen.incisional biopsy was suggestive of infiltrating lipomatosis.the patient is scheduled for an excisional surgery for esthetic purpose . a 5-year - old girl presented with the complaint of swelling on the left side of the face since birth with no history of pain or pus discharge . , there was a diffuse swelling over left cheek region , extending from infraorbital rim to lower border of mandible and anteroposteriorly from the angle of mouth to 2 cm in front of tragus [ figure 4a ] . intraoral examination revealed minor enlargement of alveolar process on the left side , early eruption of 23 , 24 , 26 , and early exfoliation of 63 and 64 . ( a ) diffuse swelling over left cheek ; ( b ) magnetic resonance imaging showing fatty infiltration magnetic resonance imaging ( mri ) showed poorly defined lipomatous lesion on the left side of the cheek , in subcutaneous plane , and buccal pad of fat , with secondary hypertrophy of maxillary alveolus and hyperplasia of left maxillary sinus . the received soft tissue specimen was measuring 1.5  0.8  0.4 cm in size , and was light brown in color , soft in consistency , and irregular in shape . the patient is being kept on a regular follow - up and no treatment has been advocated as the patient is very young . benign lipomatous tumors have been subclassified according to their histologic features and growth patterns into classic lipomas , fibrolipoma , angiolipoma , infiltrating lipomas , intramuscular lipomas , hibernoma , pleomorphic lipomas , lipoblastomatosis , and diffuse lipoblastomatosis . infiltrating lipomatosis of the face is an uncommon mesenchymal neoplasm in which mature adipocytes invade the adjacent tissue and is extremely rare in the head and neck region . while rare , it remains a definite clinical entity . the phenotypic features include soft - tissue and skeletal hypertrophy , premature dental eruption , and regional macrodontia . the etiology , natural history , optimal management , and relationship to other disorders of fatty overgrowth are unclear . there is a high risk for regrowth after resection that is , perforce , subtotal . it occurs after the third decade of life and involves subcutaneous tissue , muscles , and bones . out of our four reported cases , males and females are usually affected equally ; there is no predilection between the right and left sides of the face . the condition involves cheek , buccal sulcus , tongue , lip , floor of the mouth , mental area , and parotid gland . the lipomatosis lesion found in childhood includes congenital infiltrating lipomatosis of the face , diffuse lipomatosis , nevus lipomatosis cutaneous superficialis , michelin tire baby syndrome , and macro encephelia ( bannayan - zonana syndrome ) . out of the four cases reported here , two cases were congenital infiltrating lipomatosis . according to heymans et al . the possible mechanisms for lipomatous change that have been proposed are trauma , chronic irradiation , muscular metaplasia , degenerative processes with fatty transformation , multipotent cells of embryonic origin under the influence of hormones , congenital cytomegalovirus infection , and alteration in chromosome 12 . infiltrating lipomatosis presents with a diffuse large swelling on the side of the face that is soft , fluctuant , and non - tender . the clinical features of facial lipomatosis include unilateral hypertrophy of soft tissues of the face , most commonly the cheek , with underlying fat infiltration and skeletal overgrowth,[1681022 ] cutaneous capillary blush ( usually after resection ) , macrodontia on the affected side , abnormal root formation , early eruption of deciduous and permanent teeth on the affected side , macroglossia , and protuberances on the tongue and buccal mucosa , which are representative of underlying mucosal neuromas . differential diagnosis includes proteus syndrome , hemifacial hypertrophy , encephalocraniocutaneous lipomatosis , hemihyperplasia - multiple lipomatosis syndrome , bannayan imaging evaluation of soft tissue tumors has undergone a dramatic evolution with the advent of ct and mri , which are useful for definite differential diagnosis . classic lipomas have ct and mri signal intensity characteristics similar to those of subcutaneous fat . on ct scans , lipomas appear as homogenous hypoattenuated masses ( apart from thin and wispy soft tissue attenuated septa , although on occasion , septa may be thick and nodular ) . they have a ct number ranging from 60 to 120 hu and do not typically show contrast enhancement . in case 2 , cect of the face revealed right masseter and buccinator appearing heterogeneous with areas of fat attenuation within . on mr images , fat has typical signal intensity . on t1-weighted images , lipomas tend to have high signal intensity that diminishes with progressive t2 weighting . mri provides better tumor delineation because it has superior soft tissue contrast resolution and clear definition of the location and longitudinal extent of the mass . in the presented cases , mri showed poorly defined lipomatous lesion . ultrasonography ( usg ) may show adipose tissue , but can not delineate the real extent of the lesion . bone changes in congenital infiltrating lipomatosis of face include sclerosis and hyperplasia o f the skull , cervical vertebrae , hemimandibular hyperplasia ( including ramus , condylar process ) , accelerated dentoskeletal growth , and zygomatic hyperplasia . in one study by sahai et al . , congenital infiltrating lipomatosis of the face has also been associated with temporomandibular joint ( tmj ) remodeling , showing hyperplasia of the condylar process and eventually ankylosis . these changes could be related to increased vascularity , periosteal irritation from overlying mass , or regional mesenchymal malformation . in case 4 , mild flattening of the right condylar head was noted , which may represent secondary degenerative arthropathy . a biopsy is almost always needed to establish diagnosis and is done in all cases . in gross appearance , the lesion is a brown and yellow - colored mass , irregular in outline , and soft to firm in consistency . there is variability in size ranging from small bits less than 2  0.5  1.5 cm to large masses measuring almost 8  7 cm . the histopathologic examination shows non - encapsulated proliferation of mature adipose tissue surrounded by an extensive capillary network . there is diffuse infiltration of adjacent soft tissue and presence of fibrous tissue with various nerve bundles and thickened wall vessels . the absence of lipoblasts and signs of malignancy in spite of a rapid growth rate is observed . in all our cases , the histopathologic examination revealed adipocytes infiltrating the adjacent tissue and muscle planes , suggestive of infiltrating lipomatosis . the expression of angiogenic and vasculogenic factors has revealed that neovascularization does not seem to play a role in the pathogenesis of this condition . treatment is primarily for esthetic reasons , and can vary as per the age of the patient and the rate of recurrence . although the tumors are benign , the rate of recurrence is very high after surgical excision . though lipomatous degeneration may occur , there is no report of a frank malignancy . among our cases , case 1 and 2 had undergone complete surgical excision and case 3 is scheduled for a surgery . case 4 , being 5 years old , is kept on a regular follow - up . recurrence was seen in three out of the four cases . in conclusion , infiltrating lipomatosis of the face is a rare benign condition with no age or gender predilection . it is characterized by diffuse infiltration of fat in the subcutaneous and muscle planes and bony hypertrophy . clinical examination
infiltrating lipomatosis of the face is a very rare entity which is characterized by the collection of non - encapsulated mature adipocytes infiltrating local tissues , resulting in craniofacial deformities . 
 psychomotor development of the patients is normal , esthetics often being the primary concern to seek treatment . the presentation is always unilateral with hypertrophy of hard and soft structures on the affected side of the face . 
 the pathogenesis of the condition is unclear . 
 this condition shows a wide phenotypic range , uncertain prognosis with high rates of recurrence after surgery , and variable post - op cosmetic improvement . 
 the condition shows no gender predilection , with most of the cases presenting in and beyond the second decade of life . here , 
 we present a series of four cases presenting in varying age groups with history of recurrence in three cases .