Unusual behaviour of an unusual tumour: calcitriol-induced hypercalcaemia in metastatic oesophageal neuroendocrine carcinoma.

Filip Ionescu, Beaumont Health
Ioana Petrescu, Beaumont Health
Maria Marin, Beaumont Health


Hypercalcaemia in malignancy is most commonly caused by paraneoplastic secretion of parathyroid hormone-related protein or osteolytic metastases. Very rarely (<1% of cases), the mechanism behind increased serum calcium is increased production of calcitriol (1,25-dihydroxyvitamin D) and even rarer is the occurrence of this phenomenon in solid malignancies, with few such instances reported in the literature. We present a case of a neuroendocrine malignancy originating in the oesophagus associated with calcitriol-induced hypercalcaemia, a phenomenon that has not been previously described. We review the pathophysiology of calcitriol-induced hypercalcaemia and previously reported cases of solid tumours with this presentation.