胃切除後にみられたinsulinomaの1例

A Case of Insulinoma after Gastrectomy

　過剰なインシュリンの分泌によって低血糖症状を来たす膵臓の機能性腫瘍であるinsulinomaについては，最近ではその報告例は相い次いでなされているが，まれな疾患の1つであることに変わりはない．

　最近，私どもは胃切除後にみられたinsulinomaの1例を経験したが，本症例は胃切除後にみられ，低血糖症状を呈する後期ダンピング症候群との鑑別に甚だ難渋したので，その概要を報告するとともに，その鑑別点についても検討を加えた．

　We have experienced a 51-year-old male case of insulinoma after gastrectomy. As the hypoglycemic attacks occurred during the fasting period, our difficulty lay in its differentiation from the late dumping syndrome that shows postgastrectomy hypoglycemia. For the differential diagnosis, a 50 g GTT, a tolbutamide test and a fasting plasma insulin determination were performed. The fasting blood sugar was as low as 50～70 mg/dl. The 50 g GTT gave a low plateau curve. In the tolbutamide test, the fall in blood sugar level was prolonged and marked, coming down to 74％ of the value before tolbutamide injection. And the fasting level of plasma insulin was slightly elevated to 50～64 μu/dl. From these results, the patient was strongly suspected of insulinoma and exploratory laparotomy was done. An adenoma was found in the pancreas tail and pancreastail resection was done under the clinical diagnosis of insulinoma. This tumor was histologically confirmed as an insulinoma. He made satisfactory progress in recovery and was released from disturbances due to hypoglycemia.

　We tend to dispose of hypoglycemic symptoms after gastrectomy easily as of the late dumping syndrome. If the diagnosis of insulinoma, though it was made in this case, were not done, there may be some risk of missing a chance for the radical cure. This experience teaches us that the diagnosis of post-gastrectomy hypoglycemia must only be made after enough examinations.