Coexistence of giant cell tumor of tendon sheath and enchondroma in the middle phalanx of the little finger mimicking a malignant tumor: A case report.

Giant cell tumor of the tendon sheath is a type of slow-growing benign soft tissue tumor that typically arises from the synovium of the tendon sheath. Enchondroma is a benign bone tumor comprising of mature hyaline cartilage that centrally develops within the tubular bone. While giant cell tumor of the tendon sheath or enchondroma are common benign soft tissue and bone tumors, respectively the simultaneous occurrence of these tumors in the same region of the hand is exceedingly rare, and it can mimic a malignant tumor, thereby making the diagnosis more challenging. Herein, we report an unusual imaging presentation of the coexistence of these tumors in the middle phalanx of the little finger, which to the best of our knowledge has not been previously reported, and this initially present as a single intrinsic osseous lesion mimicking malignancy. The coexistence of these tumor types must be considered in the differential diagnosis of an intramedullary lytic lesion with a poor margin associated with a soft tissue mass of the fingers, and a meticulous preoperative magnetic resonance imaging investigation was required.