tenosynovial chondromatosis in finger, mimicking neoplastic lesion

Tenosynovial chondromatosis is an extremely rare, extra-articular variant of synovial chondromatosis. it is often mistakenly considered a cartilage or soft tissue tumor. this condition primarily affects the tendon sheath, commonly in the hands or feet. it typically presents as a gradually enlarging soft tissue mass that may be painful or restrict joint movement. in its early stages, plain radiographs may not show any abnormalities. this report discusses a case featuring a multinodular proliferation of cartilage, bone erosion, and a periosteal reaction located deep in the flexor tendons of the index finger.