This report describes the case of a 31-year-old man with a tenosynovial giant cell tumor in the left ankle region. The tumor developed over a period of 5 months. A conservatively treated fracture of the leg in the patient's history was important. The presurgical magnetic resonance imaging (MRI) examination allowed a specific diagnosis and the exclusion of infiltrative properties of the tumor. The tumor was excised using an exclusively arthroscopic technique. The procedure included treatment of intra-articular pathologies and the removal of 2 loose bodies. The excision was complete and no recurrence or complication was seen in 5 months' follow-up. In view of the possible recurrence (in about 50% of patients) and the unknown development of malignant tumors, arthroscopic excision can be advantageous. This procedure includes small scars and lower risks of infection and necrosis. Therefore, arthroscopic treatment of soft tissue tumors near the ankle joint may by an alternative to open excision.