Giant cell tumour of tendon sheath mimicking nodal osteoarthritis.

Giant cell tumour of the tendon sheath (GCTTS) commonly presents as a slow-growing and painless soft-tissue lesion in the hand. It has a propensity to mimick other benign and malignant lesions of the hand including lipoma, haemangioma, myxoid cyst, synovial sarcoma, aneurysmal bone cyst, fibroma and osteosarcoma. GCTTS has a unique histopathological appearance that aids in definitive diagnosis. Although bony invasion and local aggressive characteristics have only been reported rarely, the treatment of choice is local excision. The following case illustrates a fairly typical presentation of GCTTS with certain atypical features.