Unusual behaviour of an unusual tumour: calcitriol-induced hypercalcaemia in metastatic oesophageal neuroendocrine carcinoma.
BMJ Case Rep
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.
Ionescu F, Petrescu I, Marin M. Unusual behaviour of an unusual tumour: calcitriol-induced hypercalcaemia in metastatic oesophageal neuroendocrine carcinoma. BMJ Case Rep. 2020 Aug 25;13(8):e235209. doi: 10.1136/bcr-2020-235209. PMID: 32843450; PMCID: PMC7449358.