Calcitonin-secreting tumor of the pancreas.

Pancreatic endocrine tumors (PETs) are unusual tumors arising from cells belonging generically to the amine precursor uptake and decarboxylation systems. We present a case of a calcitonin-secreting PET in a 56-year-old female who presented with watery diarrhea, dehydration and hypokalemia. Investigation revealed hypercalcemia, hyperphosphatemia, hypercalcitonemia and a well-defined mass in the head of the pancreas on CT scan. Following a pancreaticoduodenectomy her serum calcitonin levels returned to normal and diarrhea disappeared. The identification of this particularly rare presentation of a calcitonin-secreting PET provides the opportunity to examine this pathological entity within the context of the very few previously reported instances of this disease.