Giant cell tumor of the tendon sheath originating from the ankle capsule: A case report and literature review.

Giant cell tumor of the tendon sheath (GCTTS), also termed tendosynovial giant cell tumor, is a benign, slow-growing tumor that originates from the tendon sheath or bursa. GCTTS of the foot and ankle is much less frequently reported compared with GCTTS of the hand and knee. However, GCTTS should be considered as a differential diagnosis of soft tissue tumors of the foot and ankle. The optimal treatment strategy for GCTTS in the foot and ankle is controversial due to a scarcity of cases. The present study reports the case of a patient that presented with localized intra-articular GCTTS originating from the capsule of the ankle, which is a rare anatomical location for this tumor. Considering the proximity of the tumor to the adjacent non-tumorous structures, a less radical but complete resection of the tumor was performed, followed by a hydrogen peroxide lavage. There was no evidence of recurrence during a follow-up period of 12 months, and adjuvant radiotherapy was not administered to the patient. A pre-operative diagnosis for GCTTS in the foot and ankle is mainly based on the findings of clinical examination and magnetic resonance imaging, which also facilitates the determination of a surgical strategy. For a localized tumor, an integral resection, as opposed to a radical resection, with a hydrogen peroxide lavage may result in a favorable prognosis. However, the optimal treatment for diffuse GCTTS remains to be identified.