多発性内分泌腫瘍症1型に合併した胸腺神経内分泌腫瘍

Thymic Neuroendocrine Tumor Associated with Multiple Endocrine Neoplasia Type 1

多発性内分泌腫瘍症（MEN）1型は副甲状腺の過形成，または腺腫，膵腫瘍や下垂体腫瘍を特徴とする遺伝性疾患であり，まれに胸腺神経内分泌腫瘍（NET）を合併することが知られている．われわれは，MEN 1型と診断された患者の前縦隔腫瘍摘出術を行い胸腺NETと診断した症例を経験したので，文献的考察をふまえて報告する．

Multiple endocrine neoplasia （MEN） type 1 is a hereditary syndrome characterized by hyperplasia and adenoma of the parathyroid gland, pancreatic tumor, and pituitary tumor. We report a rare case of thymic neuroendocrine tumor diagnosed after removal of a thymic tumor following pancreatic and parathyroid surgery. A 35-year-old man was diagnosed with MEN type 1 by hypercalcemia and gastrinemia with a ureteral tone. Two well defined nodules in the anterior mediastinum on computed tomography （CT）, and a high degree of accumulation on positron emission tomography （PET） was noted. Surgery was performed through a median sternotomy with anterior mediastinal tumor resection. Pathology showed thymic neuroendocrine tumor （NET）. Immunostaining results were different from pancreatic NET and duodenal NET, and a diagnosis of primary thymic NET was made. Postoperative radiation therapy was completed as adjuvant therapy, and the patient is alive without reccurrence.