Summary

Fibroma of tendon sheath should be included in the differential diagnosis for any soft tissue lesion in the hand particularly tenosynovial giant cell tumour since it is a benign tumour having a good prognosis and a timely diagnosis and prompt intervention is necessary to avoid significant anatomical and neurological complications.

Abstract

Introduction:- Fibroma of tendon sheath (FTS) is an uncommon soft tissue tumour presenting as a solitary, slow-growing, firm, painless, small nodule that shows strong attachment to the tendon or tendon sheath. It is commonly seen in hand flexor tendons. The FTS presents with atypical physical and imaging findings, it might be misdiagnosed as another soft tissue tumour such as a ganglion cyst or tenosynovial giant cell tumour, with 24% chance of recurrence after excision. We herein present a rare case of FTS of the extensor tendons of first dorsal compartment of wrist presenting with symptoms similar to de quervain’s tenosynovitis.

Case Report : - We present a case of a 23 year old female presented with 3 months history of symptoms suggestive of left wrist de quervain's tenosynovitis. With no improvement of symptoms over further 2 months, the patient was advised a local steroid injection. Post injection pain was not reduced but a localised swelling over the site of injection was developed. USG showed a hypoechoic solid nodular lesion of size 1.4x 1.2 x 0.8 cm with peripheral vascularity giving an impression of Giant Cell Tumour and not a post injection sequelae. The patient was planned for excision of the tumour. The tumour was marginally excised which was adherent to extensor tendon sheath of APL and EPB. On Histopathology a diagnosis of spindle cell fibroma of tendon sheath was made. After surgery pain & hand functions improved and no recurrence was found till followup upto 2 years. The FTS usually arises from flexor tendon sheath, but in our case it was seen arising from extensor tendon sheath. Such similar case has not been noted in the literature.

Conclusion:- Fibroma of tendon sheath should be included in the differential diagnosis for any soft tissue lesion in the hand particularly tenosynovial giant cell tumour. The clinical findings and imaging studies may provide some idea about FTS, but only histologic examination will provide a final diagnosis. The treatment of choice for FTS is complete marginal excision with its capsule. Being a benign tumour FTS has a good prognosis and overall outcome, a timely diagnosis and prompt intervention is necessary to avoid significant anatomical and neurological complications.