A rare case of pancreatic adenocarcinoma and subsequent metastatic insulinoma causing severe hypoglycemia

Abstract

Objective: To report an unusual case of concurrent pancreatic adenocarcinoma and metastatic insulinoma causing severehypoglycemia in a patient with diabetes.

Methods: The clinical presentation, biochemical studies, and relevant imaging of this patient are presented and the pertinentliterature is reviewed.

Results: A 59-year-old man with a history of unresectable pancreatic adenocarcinoma and diabetes was admitted for persistenthypoglycemia, meeting all criteria for Whipple’s triad and requiring high-dose dextrose infusion. Prior outpatient abdominalimaging had revealed hepatic lesions that were biopsied and found to be a high-grade neuroendocrine carcinoma. On admission, laboratory evaluation revealed inappropriately suppressed beta-hydroxybutyrate levels, and inappropriately elevated insulin, C-peptide, and proinsulin levels. An octreotide scan revealed uptake in the hepatic lesions but not in the pancreatic head mass. Immunohistochemistry staining of prior liver biopsy samples was negative for insulin. Diazoxide therapy was initiated, butdiscontinued after the onset of hypotension. The hypoglycemia resolved only after trans-arterial chemoembolization of lesionsboth in the left and the right liver lobes, in combination with continued octreotide. Unfortunately, he subsequently developedrecurrent hypoglycemia three weeks later and ultimately passed away after transitioning to hospice care.

Conclusions: Insulinomas are rare neoplasms of the pancreas that are characterized by insulin hypersecretion, which can bedebilitating and potentially life-threatening. The diagnosis of metastatic insulinoma is difficult to make in the setting of multiplecomorbidities and requires precise biochemical studies. Multiple medical treatments are available but the overall prognosis ispoor.