GHRH and insulin hypersecretion from a pancreatic neuroendocrine tumor in multiple endocrine neoplasia type 1

Abstract Acromegaly caused by ectopic growth hormone–releasing hormone (GHRH)-secreting neuroendocrine tumor (NET) is extremely rare, with cosecreting NETs even more seldom. We report a case of a female patient who presented with primary hyperparathyroidism (pHPT) and a GHRH- and insulin cosecreting pancreatic NET (pNET) and genetically confirmed multiple endocrine neoplasia type 1 (MEN1), within an undiagnosed family with various MEN1-related NETs. Due to the diagnosis of MEN1, screening for pituitary tumor was performed with biochemical evidence of acromegaly. Sellar magnetic resonance imaging revealed a sellar lesion, which was excised and compatible with somatotroph hyperplasia. Postoperatively, the patient developed severe hypoglycemia requiring hospitalization and the pNET was removed. Histopathology confirmed GHRH and insulin secreting pNET. Ectopic acromegaly in MEN1 is exceedingly rare. Patients with MEN1 often present with multiple pNETs, which may exhibit multihormonal secretion and frequently cosecrete GHRH and insulin in MEN1, while hypoglycemia may not be manifested possibly due to GH and insulin's counteractive effects on glucose metabolism.