胸腔鏡下に切除した縦隔副甲状腺囊腫の1例

Thoracoscopic surgery for mediastinal parathyroid cyst : a case report

◆要旨：縦隔副甲状腺囊腫は稀な疾患であり，胸腔鏡手術症例の報告はさらに稀である．患者は69歳，女性．高カルシウム血症，血中PTH高値，胸部CT上前縦隔に30mm大の腫瘤，^Tc-99mMIBIシンチで集積を認めた．縦隔副甲状腺腫瘍による原発性副甲状腺機能亢進症と診断し，胸腔鏡下手術を行った．前縦隔に長径70mm大の囊腫を認めた．部位判定のために併用した^Tc-99mMIBI投与後のガンマプローベでの局在診断は困難であった．囊腫を切除し，内腔に副甲状腺組織を認めたため縦隔副甲状腺囊腫と診断した．囊腫という稀な形態を呈していたため腫瘍部位判定に難渋した．胸腔鏡下手術は低侵襲であり，術式の選択肢の1つになると思われた．

　Mediastinal parathyroid cysts are a rare disease, and only five cases have been reported, in whieh thoracoscopic surgery was performed. The case is a 69-year-old woman. Hypercalcemia and high PTH level were detected by blood chemistry. Chest CT revealed a 2 cm mass in the anterior mediastinum, Scintigraphy revealed high accumulation of ^Tc-99mMIBI. Primary hyperparathyroidism by the mediastinal parathyroid tumor was diagnosed, and thoracoscopic surgery was performed. Thoracoscopy revealed 70 mm cyst in the anterior mediastinum. It was difficult to determine the location of the tumor with a gamma probe after the ^Tc-99mMIBI administration. The cysts were resected, and parathyroid composition was shown in the cyst lumen. It seemed that thoracoscopic surgery can be one of the operative choices for mediastinal parathyroid cysts.