Atsuhito Tone
National Hospital Organization, Okayama Medical Center,
1711-1 Tamasu, Kita-ku, Okayama 701-1192
Japan
Case Report
A Case of Proinsulin-Secreting Malignant Insulinoma in an Elderly Patient with Cerebral Infarction
Author(s): Kana Furushima, Atsuhito Tone, Akihiro Katayama, Izumi Iseda, Chigusa Higuchi, Keiko Tsukamoto, Tomohiko Mannami, Haruhiro Yamashita, Tetsuya Ohta, Shuichi Nomura, Ichiro Yamadori, Jun Wada, Kenichi Shikata and Kazuyuki HidaKana Furushima, Atsuhito Tone, Akihiro Katayama, Izumi Iseda, Chigusa Higuchi, Keiko Tsukamoto, Tomohiko Mannami, Haruhiro Yamashita, Tetsuya Ohta, Shuichi Nomura, Ichiro Yamadori, Jun Wada, Kenichi Shikata and Kazuyuki Hida
The diagnosis of insulinoma is sometimes challenging and the symptoms of hypoglycemia may be overlooked in elderly patients with cerebrovascular diseases and higher cerebral dysfunction. Recently, there have been an increasing number of case reports of insulinoma secreting proinsulin without hyperinsulinemia. We report a case of proinsulinsecreting malignant insulinoma in a 72-year-old man with aphasia due to cerebral infarction. He manifested no apparent symptoms, although he was incidentally found to have recurrent hypoglycemia by plasma glucose measurements. The Fajans, Grunt and Turner indexes were all within normal range and the arterial stimulation and venous sampling (ASVS) test revealed no increase in insulin concentration. However, proinsulin concentration was markedly elevated (2470 pmol/l) and well-differentiated endocrine adenocarcinoma, malignant insulinoma, with 2 cm in .. View More»
