Differentiation between thyroidal and ectopic calcitonin secretion in patients with coincidental thyroid nodules and pancreatic tumors - a report of two cases.

Although elevated blood levels of calcitonin are considered highly indicative for the presence of medullary thyroid carcinomas, they may be observed in patients with chronic kidney disease or in consequence of ectopic calcitonin production. We report two patients who presented with excessively elevated calcitonin levels. Diagnostic work-up revealed a single thyroid nodule and a pancreatic tumor with ectopic calcitonin secretion in both of them. On the basis of these case reports, the diagnostic work flow and management in case of clearly elevated calcitonin levels are described and discussed.