肩関節部に発生した樹枝状脂肪腫の1例

Lipoma Arborescens Arising from the Shoulder. Case Report

　症例は73歳の女性で，3カ月前から持続する左肩の疼痛と腫脹を認めて当院を受診した．MRIで三角筋下包内にT2強調像で高信号を呈する液体貯留所見と内部にT1・T2強調画像で皮下脂肪と同程度の高信号を呈する不整な滑膜組織の増生を認めた．滑膜切除術を施行し，病理組織学的に樹枝状脂肪腫と診断された．術後から左肩の疼痛・腫脹は軽快し，術後4年の現在，症状の再発は認めない．樹枝状脂肪腫が肩関節の三角筋下包に発生することは極めて稀で，これまでに6例の報告例があるに過ぎない．

　A 73-year-old woman presented with a 3 month history of left shoulder pain.　MRI revealed a subdeltoid bursal effusion of high signal intensity on the T2-weighted images and irregular synovial hypertrophy manifested as high signal intensity on both the T1-weighted and T2-weighted images within the bursa.　Synovectomy of the lesion was performed, and the histological diagnosis was a lipoma arborescens.　As of four years after the operation, the outcome has been favorable, and the symptoms have never recurred.　Lipoma arborescens arising from the subdeltoid bursa of the shoulder is very rare, and only six cases have ever been reported.　We report a rare case of lipoma arborescens arising from the subdeltoid bursa.