Today’s case involved a 62 yo M presenting with constipation, fatigue and lower extremity weakness. His labs are significant for severe hypercalcemia with a normal phosphorus. He is diagnosed with hypercalcemia due to PTHrP secretion, with no known history of malignancy. After a CT scan of his chest, abdomen and pelvis, he is found to have multiple liver lesions as well as a large pancreatic mass and biopsy of a liver lesion reveals well differentiated neuroendocrine carcinoma, likely pancreatic primary.
Take home points from today’s case:
– The first test to order for hypercalcemia is a PTH level, as primary hyperparathyroidism is the most common cause.
– If the PTH is low, should order PTHrP as humoral mediated hypercalcemia is the most common cause of non PTH mediated hypercalcemia.
– If PTHrP is not elevated, can consider other causes such as osteolytic lesions, vitamin D toxicity (can see hyperphosphatemia), increased production 1,25-dihydroxyvitamin D.
– In a patient with bone pain, renal failure and hypercalcemia, should think of Multiple Myeloma. Remember that MM can present with a low anion gap.
– In the presented patient, the PTHrP was elevated, prompting evaluation for a malignancy. Common malignancies associated with PTHrP production include squamous cell carcinomas, renal carcinoma, and breast carcinomas.
Pancreatic neuroendocrine tumors (NET) can be functioning (insulinoma, gastrinoma, glucagonoma, VIPoma) or nonfunctioning (do not present clinically with a hormonal syndrome). There are a few case reports of patients with pancreatic NET presenting with PTHrP secretion. Despite the presentation of hypercalcemia with imaging consistent with a pancreatic NET tumor, biopsy is still necessary to confirm the diagnosis.
**In a younger patients presenting with pancreatic NET, consider referral for genetic testing for hereditary endocrinopathies such as MEN 1, Von Hippel Lindau, and NF1.
Thank you Jaehoon for teaching us about pancreatic NETs and hypercalcemia!