Abstract: SA-PO0623
Hypercalcemic Crisis Unmasking Genetically Confirmed Multiple Endocrine Neoplasia Type 1 with Metastatic Pancreatic Neuroendocrine Tumor (NET G3)
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Case Reports - 2
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid, Electrolytes, and Acid-Base Disorders
- 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical
Authors
- Sarwat, Ahmed, Baystate Medical Center, Springfield, Massachusetts, United States
- Abdullin, Marat, Baystate Medical Center, Springfield, Massachusetts, United States
- Landry, Daniel L., Baystate Medical Center, Springfield, Massachusetts, United States
Introduction
Multiple Endocrine Neoplasia Type 1 is an autosomal dominant disorder characterized by parathyroid, pituitary, and pancreatic neuroendocrine tumors. Primary hyperparathyroidism is typically indolent; hypercalcemic crisis as the initial presentation is uncommon.
Case Description
A middle-aged man presented with fatigue, nausea, and vomiting and was found to have severe hypercalcemia (calcium 18.1 mg/dL, ionized >2.2 mmol/L), hypophosphatemia, and markedly elevated parathyroid hormone (>493 pg/mL), consistent with hypercalcemic crisis. He underwent subtotal parathyroidectomy with removal of three enlarged glands.
Further evaluation revealed markedly elevated glucagon (>1300 pg/mL). Imaging demonstrated a pancreatic tail mass and innumerable hepatic lesions. Biopsy of both pancreatic and liver lesions confirmed a well-differentiated neuroendocrine tumor, WHO grade 3, with Ki-67 of 37.1% and no features of neuroendocrine carcinoma. Pituitary MRI revealed a 6 mm microadenoma with hyperprolactinemia, and cabergoline was initiated.
Given multiglandular hyperparathyroidism, pituitary adenoma, and pancreatic neuroendocrine tumor, genetic testing confirmed a pathogenic MEN1 variant. Family history was notable for hyperparathyroidism, and cascade counseling identified a sibling with a pancreatic lesion under evaluation. The patient was started on Octreotide therapy.
Discussion
This case highlights hypercalcemic crisis as an uncommon initial manifestation of Multiple Endocrine Neoplasia Type 1. While pancreatic neuroendocrine tumors in MEN1 are often indolent, this patient had metastatic, well-differentiated grade 3 disease, emphasizing biologic heterogeneity. Distinguishing NET G3 from neuroendocrine carcinoma is critical due to differences in management. Genetic confirmation enabled cascade screening with identification of a potentially affected sibling.
Hypercalcemic crisis should prompt evaluation for MEN1. Early recognition of aggressive tumor phenotypes and genetic diagnosis is essential for management and family screening.