胸腔鏡下に切除した縦隔内脂肪腫の1例

A case of thoracoscopically resected mediastinal lipoma

◆要旨：患者は55歳，男性．検診で胸部異常陰影を指摘され，胸部CT，MRIで精査を行うと上縦隔に境界明瞭で内部均一な脂肪濃度を示す腫瘤を認めた．本人の希望もあり，診断目的に胸腔鏡下縦隔腫瘍切除術を施行した．術後病理診断では縦隔脂肪腫であった．術後経過は良好であり現在も再発などの所見は認めていない．縦隔脂肪腫は，本邦においてかなり稀な疾患である．診断はCT，MRIなどの画像検査によりなされるが，脂肪肉腫との鑑別が困難なことがあり，診断目的に手術を施行することが望ましい．縦隔脂肪腫摘出後に脂肪肉腫として再発した症例や，複数回手術の後に悪性化した症例も報告されており，術後の定期的な経過観察が必要である．

　A 55-year-old man was noted to have an abnormal shadow in the chest on a medical examination. Chest CT and MRI revealed a mass with a homogeneous fatty density and clear borderline in the middle mediastinum. Thoracoscopic resection of the mediastinal tumor, requested by the patient, was performed for diagnosis. A pathological diagnosis of mediastinal lipoma was made postoperatively. The postoperative course has been uneventful, without any findings such as recurrence. Mediastinal lipoma is a very rare disease in Japan. Diagnoses are made based on imaging studies, including CT and MRI, but differentiation between the disease and liposarcoma is sometimes difficult, and, hence, surgery is recommended for diagnosis. Cases of liposarcoma recurrence following mediastinal lipoma resection as well as malignant degeneration after multiple surgeries have been reported. Regular postoperative follow-up is necessary.