Pigmented Villonodular Synovitis of the Flexor Hallucis Longus Tendon Treated by Means of Tendoscopy and Endoscopic Synovectomy.

Pigmented villonodular synovitis (PVNS) of the tendon sheath (tenosynovial giant cell tumor) is a rare disorder that is often misdiagnosed because of slow growth and an atypical presentation. Open surgical excision is the treatment of choice, although recurrence is a common complication. In this report, a case of PVNS of the flexor hallucis longus tendon in the ankle and hindfoot is described. The diagnosis was confirmed by endoscopic inspection and biopsy, and complete synovectomy was performed through the endoscope. The patient remained disease free after 24 months of follow up.