Endocrine Abstracts

Introduction: A glucagonoma is a rare neuroendocrine tumor that originates almost exclusively in the pancreas and probably accounts for 1% of all neuroendocrine tumors. MEN1¹ is characterized by the development of primary hyperparathyroidism (PHPT), pancreatic neuroendocrine tumors and pituitary adenomas.

Methods: We present the case of a 39-year-old female, with history of type 2 diabetes mellitus and hypokalemia² who presented to the “C.I Parhon” National Institute of Endocrinology with repeated low potassium levels in the last year. Endocrine tests showed secondary hyperaldosteronism (renin 341.8 pg/ml, aldosterone 371 pg/ml), primary normocalcemic hyperparathyroidism (PTH 584 pg/ml) and hyperprolactinemia (69.63 ng/ml). The serum potassium level was low (1.9–2.7 mEq/l), totally asymptomatic. Abdominal MRI revealed a pancreatic corporeal-caudal tumor (40/10 mm) with an appearance compatible with a neuroendocrine tumor, with secondary lymph node, liver determinations and bilateral adrenal tumors. Fine needle aspiration from the pancreatic tumor revealed atypical cells for a neuroendocrine tumor proliferation. Neuroendocrine tumor markers: Cromogranin A 1700 ng/ml, glucagon 1329 ng/l. Pituitary MRI: left pituitary adenoma 1.03/1.05 cm. Normal pituitary function. Radionuclide Technetium 99m SESTAMIBI scan was positive for left inferior parathyroid.

Results: Corporal-caudal splenopancreatectomy en bloc with partial left adrenalectomy and enucleoresection of cephalopancreatic exopthytic tumor was performed. The pathology and IHC examination certifies well-differentiated neuroendocrine tumor G1 pT3 pN1 pM1a and AE1-AE3 positive chromogranin and synaptophysin in the tumor, negative CD56 and Ki67<1%. Microwave ablation of liver tumor segment VII. Lanreotid autogel was started. Despite sustained increased PTH values, the calcium level was normal during the follow up for 4 years.

Conclusions: The renin co-secretion from a glucagonoma is a very rare combination, with only few cases reported in literature. The hypokaliemia is severe and may be corrected after tumor debulking and systemic therapy of metastatic disease, but the prognosis is poor. Another rare occurrence is normocalcemic primary hyperparathyroidism in MEN 1 syndrome.

Keywords: glucagonoma, hypokalemia, MEN 1, secondary hyperaldosteronism.

References: 1. Singh G, Mulji NJ, Jialal I. Multiple Endocrine Neoplasia Type 1. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536980/.