小児に発症した膝滑膜性骨軟骨腫症の1例

Synovial Osteochondromatosis of the Knee in Childhood. Case Report

　滑膜性骨軟骨腫症の症例報告は散見されるが，小児発症の報告例は少ない．今回外傷を契機に発症したと考えられる小児の膝滑膜性骨軟骨腫症の症例を経験したので報告する．症例は11歳の女児で主訴は左膝関節痛であった．跳び箱から落ちて膝を打ち受傷した．いったん症状は軽快したが，しばらくしてジャンプ着地時に左膝関節痛が出現するようになった．単純X線とCTで左膝関節後外側に石灰化陰影を認めたため，関節鏡下に遊離体を摘出した．病理学的精査によって滑膜性骨軟骨腫症と診断した．現在，症状再発は認めず，経過観察中である．

　We report a rare case of synovial osteochondromatosis of the knee in childhood that developed after an injury.　An 11-year-old girl experienced left knee pain after falling from a vaulting horse.　X-ray films and CT scans revealed calcified bodies in the posterolateral part of the left knee.　During arthroscopic surgery, 6 loose bodies were detected immediately medial to the popliteal tendon and under the lateral meniscus.　No clear evidence of synovial inflammation was found.　A diagnosis of synovial osteochondromatosis was made as a result of histological examination of the loose bodies.　The patient has been followed up for 3 years, and she is symptom-free with no radiological evidence of recurrence.