Gutelius Bruce J, Korytkowski Mary T, Carty Sally E, Hamad Giselle G
Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
Am Surg. 2007 May;73(5):520-4.
Insulinomas are rare endocrine tumors that are usually diagnosed by inappropriate elevations in insulin and C-peptide during hypoglycemia. We report a case of a surgically confirmed insulinoma diagnosed by a mild elevation in proinsulin with suppressed insulin and C-peptide at the time of hypoglycemia during a supervised fast. A supervised fast with serial measurements of plasma glucose, insulin, and C-peptide was performed in a patient with documented hypoglycemia. Proinsulin was measured at the beginning and end of the fast. Tumor localization was accomplished with spiral CT, magnetic resonance imaging, and endoscopic ultrasound. Minimally invasive tumor resection was performed. The presence of an insulinoma was confirmed on the basis of a minimally elevated proinsulin level with a suppressed insulin level at the time of symptomatic hypoglycemia. Tumor resection was performed without complications, resulting in resolution of the hypoglycemia. This case demonstrates the importance of measuring proinsulin as a routine component of the 72-hour fast for detection of an insulinoma. Even mild elevations in circulating proinsulin can be an independent indicator of aberrant insulin secretion during hypoglycemia. Once the diagnosis of insulinoma is made and tumor localization is achieved, minimally invasive tumor resection is a safe and effective treatment modality.
胰岛素瘤是一种罕见的内分泌肿瘤，通常通过低血糖期间胰岛素和C肽不适当升高来诊断。我们报告一例经手术证实的胰岛素瘤病例，该病例在监督性禁食期间低血糖时，胰岛素和C肽受到抑制，但胰岛素原轻度升高，据此得以诊断。对一名有低血糖记录的患者进行了监督性禁食，并连续测量血浆葡萄糖、胰岛素和C肽。在禁食开始和结束时测量胰岛素原。通过螺旋CT、磁共振成像和内镜超声进行肿瘤定位。进行了微创肿瘤切除术。根据有症状低血糖时胰岛素原水平轻度升高且胰岛素水平受到抑制，证实存在胰岛素瘤。肿瘤切除术后无并发症，低血糖症状得以缓解。该病例表明，在72小时禁食检测胰岛素瘤时，将测量胰岛素原作为常规项目具有重要意义。即使循环胰岛素原轻度升高也可能是低血糖期间胰岛素异常分泌的独立指标。一旦确诊胰岛素瘤并实现肿瘤定位，微创肿瘤切除术是一种安全有效的治疗方式。
