Overtly Manifested Diabetes Mellitus after Resection of Insulinoma

Abstract

Insulinoma is the most common cause of endogenous hyperinsulinemic hypoglycemia in adults. However, the coincidence of insulinoma and diabetes is extremely uncommon. We describe a rare, but very interesting case of diabetes mellitus which was masked by insulinoma and was overtly manifest after the removal of the insulinoma.

Early Postoperative Fasting Serum Glucose Levels are Useful in Depicting Future Diabetes Mellitus in Patients with Curative Insulinoma Surgery

“…The accepted cause of diabetes mellitus in these patients may be explained by the wide excision of functional islets during tumor resection with reduction of islet cells below a critical mass. This is in accordance with retrospective analyses in insulinoma patients that show diabetes mellitus more often in patients after insulinoma surgery when pancreatic resection has been performed than after enucleation of tumor tissue, only [3].…”

“…Some of these patients have suffered from a coexisting diabetes mellitus [10] and it occurred that diabetes mellitus was only masked by the activity of an insulinoma. In these patients the prior illness of diabetes mellitus manifested again after resection of the insulin producing tumor [3]. In some rare cases with persisting diabetes mellitus, however, no history of prior diabetes mellitus was evident, as it was not in the only one of our 77 patients (1.3 %) with permanent diabetes mellitus.…”

“…Beside this, the early postoperative glucose metabolism in patients with successfully resected insulinomas has not been subject for systematic investigations, to our knowledge. Only few reports of pathologic postoperative serum glucose levels above 200 mg/dl and even fewer anecdotal experience with long-term Diabetes mellitus, in these patients, have been published [2,3]. Despite the generally accepted downregulation of insulin receptors in patients with pancreatic hyperinsulinism, little is known about the course and length of the altered glucose metabolism in insulinoma patients after curative surgery.…”

Type 2 diabetes mellitus in a patient with malignant insulinoma manifesting following surgery

“…Ahn et al . had reported a case of diabetes mellitus that had been masked by an insulinoma and manifested overt after the removal of tumour [7]. In light of the fact that it was not specifically stated whether the tumour was benign or malignant, we think that it might have been a benign insulinoma on the basis of an absence of metastasis.…”

“…Bleeding, pseudocyst, pleural effusion, intra-abdominal fluid collection and diabetes may occur after resection of any portion of the pancreas. Diabetes mellitus in particular can develop after resection of the pancreas, depending on the extent of surgery, which predicts the insulin sufficiency [7]. Malignant or metastatic insulinoma is a rare condition; therefore, there are limited data about the clinical behaviour of the disease.…”