Pigmented villonodular synovitis of the foot and ankle: a report of eight cases.

Eight cases of pigmented villonodular synovitis of the foot and ankle are reported. The purpose of this study was to analyze the manifestation of pigmented villonodular synovitis in the foot and to evaluate treatment options. There were four cases in the ankle and hindfoot, one in the first tarsometatarsal joint, and three in the toes. In seven of eight cases, diagnosis was confirmed by magnetic resonance imaging (MRI) scans. The tenosynovial form was found in the toes and the articular form in the hindfoot and ankle. Surgical treatment was performed in all cases: one arthroscopically assisted synovectomy in the ankle joint, two talocrural arthrodeses, one subtalar arthrodesis, one tarsometatarsal arthrodesis, and tumor removal on the toes with arthrodesis of the distal interphalangeal (DIP) joint in two cases. Average follow-up was 4 years. Recurrence occurred in one toe and led to partial amputation. Malunion in one ankle arthrodesis was operated on again with no sign of recurrence. In the toes, the lesion had a tumoral feature; the bone was infiltrated by soft tissue, and the surgical procedure was local removal of the tumor. In the hind-foot, the lesions were intra-articular and required synovectomy, usually with an arthrodesis. In the midfoot, there was a large extraosseous tumor surrounding tendons with destructive articular lesions.