Combined Hepatocellular Carcinoma and Neuroendocrine Carcinoma with Ectopic Secretion of Parathyroid Hormone: A Case Report and Review of the Literature

Primary combined hepatocellular carcinoma (HCC) and neuroendocrine carcinoma is a rare entity, and so is hypercalcemia due to ectopic parathyroid hormone (PTH) secretion by tumor. A 44-year old man with hepatitis B virus associated chronic liver disease presented with a hepatic mass. Hemihepatectomy discovered the mass as combined HCC and poorly differentiated cholangio-carcinoma. During adjuvant chemoradiation therapy, he presented with nausea, and multiple systemic metastases were found. Laboratory tests revealed hypercalcemia with markedly elevated PTH and neuron specific enolase. Parathyroid scan showed normal uptake in parathyroid glands, suggestive of ectopic PTH secretion. Subsequently, immunohistochemistry of neuroendocrine marker was performed on the primary lesion, and confirmed the neuroendocrine differentiation in non-HCC component. The patient died 71 days after surgery. This report may suggest the possibility of ectopic PTH secretion by neuroendocrine carcinoma of hepatic origin causing hypercalcemia. Caution for neuroendocrine differentiation should be exercised when diagnosing poorly differentiated HCC.