Giant Cell Tumor Mimicking Mucous Cyst

A mass presenting on the dorsal side of the distal inter-phalangeal joint is most commonly a ganglion cyst of that joint also called a mucous cyst. Although other tumorous conditions can mimic a mucous cyst, a giant cell tumor of the tendon sheath (GCTTS) also called tenosynovial giant cell tumor (TGCT), or a pigmented villo-nodular synovitis (PVNS) is one of those and do raise some questions regarding treatment options. Tenosynovial giant cell tumors are benign tumors of uncertain pathogenesis. They occur in the joints, tendons and synovial bursas. Due to a high recurrence rate of up to 50%, some authors call a giant cell tumor a semimalignant tumor. Complete excision is mandatory for effective treatment.


Mass overlying the distal inter-phalangeal joint gives the impression of a simple mucous cyst.







Exposure of the tumorous condition reveals a Giant Cell Tumor of the Tendon Sheath (GCTTS)







Close up view. This tumor can originate from the joint or tendon sheath and complete removal is essential to decrease the local recurrence rate.