リウマチ肩において急速に上腕骨頭の圧潰を生じた1例

Rapid Destruction of the Humeral Head in a Patient with Rheumatoid Arthritis. Case Report

　関節リウマチ（RA）患者で，急速に上腕骨頭が圧潰した症例を経験したので報告する．症例は57歳の女性で，2004年から手関節にRAを発症し，当科初診時Steinbrocker Stage Ⅲ Class Ⅱの状態であった．プレドニン10mg/日，リウマトレックス6mg/週を2年間投与されていたが，2006年12月から右肩痛が出現して徐々に増悪し，その後4カ月間の短期間で上腕骨頭の圧潰を来し，人工骨頭置換術を施行した．RAで急速に上腕骨頭が圧壊したという報告はないが，本症例では術中所見から軟骨下骨内に旺盛なパンヌスの浸潤がみられ，これが骨の脆弱性を引き起こし，非荷重関節である上腕骨頭に圧潰を呈したのではないかと考えられた．

　We report a case of rapid destruction of the right humeral head in a patient with rheumatoid arthritis (RA). The patient was 57-year-old woman with a 3-year history of RA (Steinbrocker：Stage Ⅲ, Class Ⅱ) who had experienced pain in her wrists since 2004. The patient had been taking prednisolone 10mg/day and methotrexate 6mg/week since she had been diagnosed with RA. She complained of pain in her right shoulder since December 2006 that had gradually increased. Standard radiographs showed that the collapse of the humeral head had progressed, and hemiarthroplasty was performed on the right shoulder. Although there have been no reports of rapid humeral head destruction in RA, the histopathologic findings in this case revealed a large granulomatous lesion packed into the subchondral bone of the humeral head. We attributed the granulomatous lesion to the rapid rate of bone collapse.