下腿近位に発生した関節外 PVS の一例

抄録

Pigmented villonodular synovitis (PVS) is a benign but aggressive lesion of the synovium, most commonly involving the knee joint. Knee joint is the most commonly involved site. The extraarticular form of PVS is extremely rare. We report a very rare case of extraarticular PVS of the proximal lower leg. A 35-year-old woman was referred to our hospital complaining of pain and swelling of the right lower leg. Synovial sarcoma was suspected as its diagnosis with MRI and Sono-CT. However since this tumor was histologically diagnosed as PVS, marginal resection of the tumor was performed. No recurrence of the tumor was seen for 12 months after the operation. We reviewed differential diagnoses comparing characteristic imaging features between extra-articular PVS and synovial sarcoma.