99mTc-MIBIシンチグラム陰性原発性副甲状腺機能亢進症に対して術中intact-PTH値測定により内視鏡補助下手術をしえた1例

A case of primary hyperparathyroidism in which 99mTc-MIBI scintigram failed to detect a parathyroid tumor but a complete resection was passible by video-assissted neck surgery accompanied by intraoperative quick PTH assay

◆要旨：患者は26歳，女性．繰り返す尿管結石症を契機にintact-PTH値高値から原発性副甲状腺機能亢進症と診断された．頸部超音波検査およびCT検査で甲状腺左葉上極背側に腫大した副甲状腺を認めたが，^99mTc-MIBIシンチグラムは陰性で責任病巣の局在診断には至らなかった．再検するも^99mTc-MIBIは陰性で推移したが，高Ca低P血症は持続した．腫大した副甲状腺を摘除する方針とし，術式は整容性を考慮しての内視鏡補助下手術を選択した．術中迅速intact-PTH値測定にて責任病巣摘出を確認した．病理組織診断は副甲状腺腺腫であった．術前局在診断が困難であっても，補助的手段の併用によっては安全で過不足のない内視鏡補助下副甲状腺摘除は可能と考えられた．

　We report a case, a 26-year-old woman of primary hyperparathyroidism who suffered from the complications of urethral stone attacks. Serum calcium and intact parathyroid hormone（PTH）levels were elevated, and the serum phosphorus level was decreased, which was consistent with primary hyperparathyroidism. Technesium-99 m-methoxyisobutylisonitrile（^99mTc-MIBI）scintigraphy repeatedly failed to detect any abnormal accumulation in the neck and chest, while other imaging techniques, such as cervical ultrasonography and computerized tomography demonstrated an enlarged parathyroid gland. We could not conclude whether the abnormal parathyroid gland is indicated for surgical resection, because of undectability in ^99mTc-MIBI. After consultation and careful discussion with experienced endocrine surgeons, we performed an operation to resect the parathyroid gland as a causation of hyperparathyroidism leading to urethral stones. Video-assisted neck surgery was performed and the surgical resection was carried out successfully, accompanied with the intraoperative quick PTH assay. Histological findings showed parathyroid adenoma. Video-assisted neck surgery was considered to be a feasible method with proper curability and cosmetic conservations for the treatment of parathyroid tumor, even though the preoperative imaging examinations could not definitively confirm the location of the parathyroid adenoma. In this case, the intraoperative quick PTH assay was very helpful. This case is thought to be valuable and therefore we report herein.