tumefactive fibroinflammatory lesions ( tfls ) constitute a rare idiopathic fibrosclerosing disorder . clinically , tfls mimic a malignant process due to their aggressive clinical behavior and locally destructive nature ; however , histologically they are a benign lesion . depending on the site of occurrence , organ of origin , or predominant pathological features , tfls have variably been termed  plasma cell granulomas  ,  xanthogranulomas  , or multiple synonyms are due to the rarity of these lesions and a lack of definite clinical criteria for classification . the most common sites of involvement include the head and neck region , especially the sinonasal region and the neck region . rarely the extremities may be affected . we introduce a case of this rare lesion presenting as a cheek mass with a view to contributing to the existing literature . a 29-year - old woman was admitted with a history of a rapidly increasing swelling on the cheek of 1 month s duration . the patient initially felt a dull aching pain in the right upper back tooth region , which initially responded partially to a course of antibiotics and anti - inflammatory drugs . after 2 days , she noticed swelling inside the mouth , which increased and grew large enough to appear on the cheek . the pain became throbbing and unbearable over the next few days , compelling her to seek medical attention in emergency services . a 32 cm firm , nodular , tender , noncompressible , nonfluctuant , and nonpulsatile swelling was noted on the right cheek . it extended superiorly to the infraorbital margin , medially to the alae of the nose , and laterally to 2 cm anterior to the pre - auricular region with an indistinct inferior margin . intra - oral examination revealed a firm and nodular swelling present on the right buccal vestibule extending from the 1st premolar to the 2nd molar region anteroposteriorly . radiography of the paranasal sinuses was reported as hazy along with resorption of the bony walls ( figure 2a ) , hinting at the possibility of right maxillary sinusitis . ultrasonography of the right cheek swelling revealed an irregular hypoechoic collection , 2.20.5 cm in size , seen in the muscle plain at the site of complaint , abutting the bone in the right cheek along with a hypoechoic lymph node , 2.31.1 cm in size . on contrast - enhanced computed tomography , an ill - defined and minimally enhancing soft - tissue mass , 3.43.12.4 cm in size , was seen involving the right infratemporal fossa and maxillary sinus with associated destruction of its lateral wall without any evidence of calcification / hemorrhage . anterolaterally , the mass was causing destruction of the anterior root of the zygoma with extension into the premaxillary soft tissues . superiorly , there was destruction of the floor of the orbit with an infratemporal extension , medially causing blockage of the osteomeatal complex and inferiorly destroying the maxillary bone ( figures 2b , c , and d ) . the possibility of infective etiology of a fungal origin , without ruling out malignancy , was suggested . a ) x - ray shows hazy paranasal sinuses with resorption of the bony walls . b ) , c ) , and d ) contrast - enhanced computed tomography face shows the mass on the right side . biopsy from the mucosal aspect of the cheek was received with a clinical differential diagnosis of an infective lesion ( of probably a fungal etiology ) , fibroma , and schwannoma . histopathology of the biopsy revealed fibroadipose and fibrocollagenous tissue , showing dense chronic inflammation along with the formation of lymphoid follicles . fungal stains were negative , and there was no evidence of granuloma or malignancy . although the swelling did not increase in size , a significant reduction in the swelling was not achieved and the patient continued to complain of severe pain . within a week , repeat biopsy , labeled  soft tissue right buccal mucosa  and  right upper posterior teeth region  , was submitted with special requisition again to rule out fungal infection . microscopically , it revealed stratified squamous mucosa , submucosa , and deeper fibromuscular soft tissue enclosing the lobules of the minor salivary glands along with acute on chronic nonspecific inflammation . intraoperative frozen section showed the destruction of the skeletal muscle , dense collagenization , and mild inflammation along with proliferating plump spindle cells . multiple biopsies , labelled  mass infratemporal space  ,  anterior border of the masseter muscle including the lesion  ,  anterior wall of the right maxillary antrum  , and  other soft tissues from the zygomatic arch  , were received . all the biopsies revealed almost similar histopathological features and consisted of necrotic antral mucosa , proliferating fibrous tissue , and bands of hyalinized collagen with dense chronic lymphoplasmacytic infiltrates with formation of lymphoid follicles and giant cells extending into the subcutaneous fat and septa along with varying stages of granulation tissue ( figure 3 ) . no cellular atypia or mitosis , typical or atypical , was seen even on extensive screening . based on the clinical and radiological findings ( short history , large persistent swelling with evidence of bone destruction ) , special stains including pas , gms , and zn stain ( fungus , mycobacterium ) were negative . various differentials of reactive and neoplastic processes , which give similar appearances including nodular fasciitis , proliferative fasciitis inflammatory myofibroblastic tumors ( imts ) , fibromatoses , pseudolymphomas , kaposi sarcomas , fibrosarcomas , and lymphomas were kept . further extensive screening and immunohistochemical ( ihc ) stains with a review of literature were employed for a conclusive diagnosis . on ihc , spindle cells were positive for vimentin , sma , with focal positivity for desmin and negative for cytokeratin , s-100 , and alk . the lymphoid follicles revealed polyclonal positivity , showing the coexpression of cd3 , cd5 , and cd20 in different subpopulations of the same follicles ( figure 3 ) . based on these ihc findings , the possibilities of the various differentials kept were excluded . a diagnosis of nodular fasciitis , proliferating fasciitis , and fibromatosis was ruled out due to dense inflammation , lack of a storiform pattern , and cellularity . lymphoma was ruled out due to the polyclonal nature of the lymphoid cells on ihc . complete imaging workup , including thoracic and abdominal imaging , was done to rule out other manifestations of idiopathic fibrosing conditions . a 29-year - old woman was admitted with a history of a rapidly increasing swelling on the cheek of 1 month s duration . the patient initially felt a dull aching pain in the right upper back tooth region , which initially responded partially to a course of antibiotics and anti - inflammatory drugs . after 2 days , she noticed swelling inside the mouth , which increased and grew large enough to appear on the cheek . the pain became throbbing and unbearable over the next few days , compelling her to seek medical attention in emergency services . a 32 cm firm , nodular , tender , noncompressible , nonfluctuant , and nonpulsatile swelling was noted on the right cheek . it extended superiorly to the infraorbital margin , medially to the alae of the nose , and laterally to 2 cm anterior to the pre - auricular region with an indistinct inferior margin . intra - oral examination revealed a firm and nodular swelling present on the right buccal vestibule extending from the 1st premolar to the 2nd molar region anteroposteriorly . radiography of the paranasal sinuses was reported as hazy along with resorption of the bony walls ( figure 2a ) , hinting at the possibility of right maxillary sinusitis . ultrasonography of the right cheek swelling revealed an irregular hypoechoic collection , 2.20.5 cm in size , seen in the muscle plain at the site of complaint , abutting the bone in the right cheek along with a hypoechoic lymph node , 2.31.1 cm in size . on contrast - enhanced computed tomography , an ill - defined and minimally enhancing soft - tissue mass , 3.43.12.4 cm in size , was seen involving the right infratemporal fossa and maxillary sinus with associated destruction of its lateral wall without any evidence of calcification / hemorrhage . anterolaterally , the mass was causing destruction of the anterior root of the zygoma with extension into the premaxillary soft tissues . superiorly , there was destruction of the floor of the orbit with an infratemporal extension , medially causing blockage of the osteomeatal complex and inferiorly destroying the maxillary bone ( figures 2b , c , and d ) . the possibility of infective etiology of a fungal origin , without ruling out malignancy , was suggested . a ) x - ray shows hazy paranasal sinuses with resorption of the bony walls . b ) , c ) , and d ) contrast - enhanced computed tomography face shows the mass on the right side . biopsy from the mucosal aspect of the cheek was received with a clinical differential diagnosis of an infective lesion ( of probably a fungal etiology ) , fibroma , and schwannoma . histopathology of the biopsy revealed fibroadipose and fibrocollagenous tissue , showing dense chronic inflammation along with the formation of lymphoid follicles . fungal stains were negative , and there was no evidence of granuloma or malignancy . although the swelling did not increase in size , a significant reduction in the swelling was not achieved and the patient continued to complain of severe pain . within a week , repeat biopsy , labeled  soft tissue right buccal mucosa  and  right upper posterior teeth region  , was submitted with special requisition again to rule out fungal infection . microscopically , it revealed stratified squamous mucosa , submucosa , and deeper fibromuscular soft tissue enclosing the lobules of the minor salivary glands along with acute on chronic nonspecific inflammation . intraoperative frozen section showed the destruction of the skeletal muscle , dense collagenization , and mild inflammation along with proliferating plump spindle cells . soft tissues sent for direct immunofluorescence were negative for immune deposits . multiple biopsies , labelled  mass infratemporal space  ,  anterior border of the masseter muscle including the lesion  ,  anterior wall of the right maxillary antrum  , and  other soft tissues from the zygomatic arch  , were received . all the biopsies revealed almost similar histopathological features and consisted of necrotic antral mucosa , proliferating fibrous tissue , and bands of hyalinized collagen with dense chronic lymphoplasmacytic infiltrates with formation of lymphoid follicles and giant cells extending into the subcutaneous fat and septa along with varying stages of granulation tissue ( figure 3 ) . no cellular atypia or mitosis , typical or atypical , was seen even on extensive screening . based on the clinical and radiological findings ( short history , large persistent swelling with evidence of bone destruction ) , special stains including pas , gms , and zn stain ( fungus , mycobacterium ) were negative . various differentials of reactive and neoplastic processes , which give similar appearances including nodular fasciitis , proliferative fasciitis inflammatory myofibroblastic tumors ( imts ) , fibromatoses , pseudolymphomas , kaposi sarcomas , fibrosarcomas , and lymphomas were kept . further extensive screening and immunohistochemical ( ihc ) stains with a review of literature were employed for a conclusive diagnosis . on ihc , spindle cells were positive for vimentin , sma , with focal positivity for desmin and negative for cytokeratin , s-100 , and alk . the lymphoid follicles revealed polyclonal positivity , showing the coexpression of cd3 , cd5 , and cd20 in different subpopulations of the same follicles ( figure 3 ) . based on these ihc findings , the possibilities of the various differentials kept were excluded . a diagnosis of nodular fasciitis , proliferating fasciitis , and fibromatosis was ruled out due to dense inflammation , lack of a storiform pattern , and cellularity . lymphoma was ruled out due to the polyclonal nature of the lymphoid cells on ihc . complete imaging workup , including thoracic and abdominal imaging , was done to rule out other manifestations of idiopathic fibrosing conditions . the term  tfl  was first introduced by wold and weil and in 1983 to describe lesions of the head and neck that clinically simulate a malignant process in that they are locally invasive but histologically composed of mature sclerosing fibrous lesions interspersed with normal - appearing fibroblasts and lymphocytes . coexisting fibrosclerotic processes have been seen in 20% of cases including retroperitoneal fibrosis , sclerosing cholangitis , sclerosing mediastinal fibrosis , and orbital pseudotumors . in medical literature , tfls have been described under inflammatory pseudotumors . to date , approximately only 35 cases have been reported in the literature . a wide age group is involved ranging from 10 to 74 years with a slight male predominance . the possible mechanism considered is an exaggerated immunological host tissue response to unidentified infectious agents , adjacent necrotic tissues , foreign bodies , or neoplasms or an autoimmune reaction to a previous viral infection . smoking and chronic irritation by cocaine abuse have also been suggested as triggering factors for tfls . it is , however , on histopathological examination that the diagnosis becomes clear and malignancy is ruled out . grossly , these lesions are firm and tannish - to - gray white and vary from being circumscribed to locally invasive . the histopathological features are of a benign lesion consisting of an admixture of fibrous tissue , collagen , and inflammatory cells associated with a giant cell reaction . tfls can invade the adjacent soft tissues , muscles , and neurovascular structures and can erode the underlying bone with the involvement of the meninges and the brain . hence , any mass - forming lesion with any of these features should raise suspicion of malignancy . our patient also presented with similar clinical , radiological , and histological findings . even on extensive sampling , tfl - like lesions should be differentiated from more commonly encountered lesions of the head and neck like fibromatoses , nodular fasciitis , malignant fibrous histiocytomas , and fibrosarcomas . nodular fasciitis , seen in the head and neck , is a pseudosarcomatous self - limiting process which shows a prominent whorled or feathery cellular pattern lacking inflammatory infiltrates . although tfls are infiltrative , they lack the cellularity , cellular atypia , and mitotic activity seen in malignant fibrous histiocytomas and fibrosarcomas . a differential diagnosis of tfls also includes imts , which have been categorized under inflammatory pseudotumors . imts mainly occur in the lung , but they also have been seen in the head and neck area . additionally , 50% of imts are alk positive . however , in our patient , this entity was ruled out because alk was negative . the treatment options include surgery , steroids , and radiation therapy either alone or in combination . some studies have shown steroids to be a better first - line treatment option , which may be followed by surgery and/or radiotherapy . surgery is successful in surgically accessible sites , while radiation therapy is reserved for patients who do not respond to steroids or when the tumor extent limits surgical excision . our patient was put on steroids , followed by surgical excision , but she reported back after 6 months with similar complaints . hence , these patients should be kept on regular follow - up and be assessed bearing in mind that tfls may involve multiple body sites . we introduced a rare case of tfl presenting as a cheek mass , which was biopsied for suspicion of malignancy because of its aggressive clinical presentation . reaching such lesions should be kept a possibility while dealing with clinically aggressive , invasive lesions , especially in the head and neck region , and treated appropriately .
tumefactive fibroinflammatory lesions ( tfls ) are rare idiopathic benign fibrosclerosing lesions that clinically simulate a malignancy . 
 tfls are seen more frequently in males between 10 and 74 years of age . 
 the usual site of involvement is the head and neck region , but rarely the extremities may be involved . 
 coexisting fibrosclerotic processes have been reported including retroperitoneal fibrosis , sclerosing cholangitis , sclerosing mediastinal fibrosis , and orbital pseudotumors . 
 the etiology of this poorly understood entity remains unknown . 
 possible suggestions include exaggerated responses or autoimmune reactions to any chronic infection . 
 the clinical and radiological appearance of tfls is that of malignancy , but histopathology reveals them to be a benign process broadly classified under non - neoplastic , fibroinflammatory proliferations . the treatment strategies for these lesions are not well defined and variable and include steroids , surgery , and radiotherapy either alone or in combination . 
 tfls , albeit not fatal , have a high recurrence rate ; patients should , therefore , be kept on long - term follow - up . 
 we describe a young female patient presenting with a rapidly developing cheek swelling , which was diagnosed histopathologically as a tfls .