A rare tumor of interosseous membrane forearm - Punjab ...

Case ReportA rare tumor of interosseous membrane forearmKuljit Kumar *, P Prasad **, Ankit Varshney****Assistant Professor, **Professor, ***Junior ResidentDepartment of OrthopaedicsHIMS, DehradunABSTRACT25 year old female presented with swelling on dorsal aspect of proximal third of forearm with difficulty insupination and pronation. Swelling was excised and sent for histopathological examination. Biopsy reportshowed as benign spindle cell tumor favouring fibromatosis. Extra adbominal fibromatosis from interosseousmembrane of forearm is rare presentation. Although it is rare entity differential diagnosis should be kept inmind if there is swelling in proximal third of forearm presented with restriction of supination and pronation.Because these tumors are locally aggressive, early diagnosis and treatment are crucial to minimize morbidity.Keywords: Interosseous membrane fibromatosis, Extra abdominal fibromatosisINTRODUCTIONFibromatosis, as proposed by Stout, 13 comprise a broad groupof benign fibrous tissue proliferations of similar microscopicappearance whose biologic behavior is intermediate betweenthat of benign fibrous lesions and fibrosarcoma. Likefibrosarcoma, the fibromatoses are characterized by infiltrativegrowth and a tendency toward recurrence, but unlike this tumorthey never metastasize.The fibromatosis can be divided into two major groupssuperficialand deep fibromatosis. Superficial fibromatosisarise from fascia or aponeurosis. Deep fibromatosis as namesuggests involve deep structure, particularly the musculatureof the trunk and the extremities. Deep fibromatosis isfurther divided into extraabdominal and intra abdominalfibromatosis. The descriptive term desmoid tumor, coined byMueller in 1838, is still widely used in the literature as asynonym for fibromatosis. It is estimated that 3-4 cases of extraabdominal fibromatosis per million occur in United Statesannually 2 . Although extra abdominal fibromatosis frominterosseous membrane is rare entity, differential diagnosisshould be kept in mind if there is swelling in proximal third offorearm presented with restriction of supination andpronation.CASE REPORTA 25 year old female presented with a swelling on the back ofher right forearm since 3 ½ years. Swelling was small at onsetand gradually increased in size. It was associated with nonradiating,mild pricking type of on and off pain. There was nohistory of significant trauma, weight loss, fever and loss ofappetite.On physical examination there was a single 8 X 4 cm firm,non-tender swelling over the dorsal aspect of the right forearm5 cm below the elbow joint. The margins were not welldemarcated and the swelling was attached to the underlyingsoft tissue. There were no signs of inflammation. The distalneurovascular status was normal. Range of movement were-Supination (0-10) 0 , Pronation (0-20) 0 . Range of movements ofelbow and wrist were normal. Radiographic evaluation revealedCorresponding Author :Dr. Kuljit KumarDepartment of Orthopaedics,HIMS, DehradunEmail: koolguy0062008@yahoo.comFig1. AP X-ray of forearmPb Journal of Orthopaedics Vol-XIII, No.1, 201279

A rare tumor of interosseous membrane forearmFig 5. Clinical photo showing tumor massFig 6. Clinical photo showing tumor massFig 7. Clinical photo showing tumor massFig 8. Tumor mass after excisionFig 9. Cross-section after excision of tumor massarise from interosseous membrane of forearm and not from anymuscle. The recurrence rate recorded in literature for extraabdominal fibromatoses is ranging from as low as 19% 4 to asFig 10. Clinical photo showing forearm after tumor mass excisionhigh as 77%. 8 Numerous studies have found that the extent ofinitial excision is prognostically significant. 5,7,11 Because themicroscopic picture does not reliably reflect the growth potentialof the tumor, therapy is predicated on its extent and anatomicalPb Journal of Orthopaedics Vol-XIII, No.1, 201281