Hypercalcitoninemia and Insulinoma – a rare association

Calcitonin is a crucial biochemical marker used in the monitoring of patients with medullary thyroid carcinoma. However increased levels of circulating calcitonin may also be associated with other clinical conditions, namely pancreatic neuroendocrine tumours (PanNETs). The incidence of calcitonin secretion by these tumours is unknown. We describe a case of a 72-year-old man who presented with lipothymia and paraesthesias of the mouth and hands associated with severe pre-prandial hypoglycaemia. Diagnostic work-up revealed an insulinoma with immunostaining for calcitonin. It is worth to mention that a subjacent hypercalcitoninemia was found. Additionally, we perform a review of the related literature. Our case highlights a very rare cause of hypercalcitoninemia and the need for a better understanding on the implications of calcitonin secretion by PanNETs. Hypercalcitoninemia and Insulinoma: A Rare Association