Giant Cell Tumor of Extensor Tendon Sheath in Ring Finger: A Case Report

Giant cell tumour of the tendon sheath (GCTTS) is a rare benign soft tissue tumour with no known cause. It is more prevalent in the hand than in the ankle and foot. It appears as a non-painful, perceptible enlargement. Although pre-operative imaging and fine-needle aspiration cytology (FNAC) corroborate suspicion, histology following surgical resection is used to confirm the diagnosis. Due to its rarity, a case of giant cell tumour (GCT) of the extensor tendon sheath of the left ring finger is reported here. A 39-year-old female presented with a six-month history of painless swelling over left ring finger. The swelling was spontaneous, slowly progressive and painless. On clinical examination, a 1.5 cm x 1 cm firm swelling was seen on the dorsal surface of the left ring finger extending from the distal portion of the middle phalanx to the proximal half of the distal phalanx. The swelling was well-defined, smooth, firm, and uniform in consistency. The swelling was movable sideways with no attachment to the bone when examined clinically. X-ray of the hand showed soft tissue mass without the involvement of the bone. Soft tissue mass was seen on ultrasonography. An excisional biopsy was done. Histopathology showed typical features of GCTTS. Our case is a rare example of GCTTS in a single digit of the hand. Furthermore, considering its high recurrence risk, the tumour should be totally excised. Finally, if required, the hand's function should be recreated to minimise the loss.