Parathyroid Hormone related Peptide secretion from a Pancreatic Neuroendocrine tumour. A rare case report of severe hypercalcaemia.

Abstract

Background/ObjectiveHypercalcemia is a common occurrence associated with malignancy, due to a number of causes: lytic bone metastases, production of 1,25 dihydroxyvitamin D from lymphoma, and parathyroid hormone related peptide (PTHrP) secretion usually from solid tumours. Case ReportA 56 year old female presents with symptoms of severe hypercalcemia. Investigations determined this was due to PTHrP secretion from a pancreatic neuroendocrine tumour (pNET), a noted complication in 1.1% of pNET cases. Although unfit for curative therapy, the patient was treated with fluid replacement, bisphosphonates, calcitonin and denosumab. Following treatment, she had recurrent severe symptomatic hypercalcemia on several occasions despite adjunctive therapy with a somatostatin analogue. Ultimately, the patient died as a result of refractory hypercalcemia. DiscussionThe hypercalcemia that is rarely associated with PTHrP secretion from pNETs is aggressive and often refractory to the usual medical treatment of hypercalcemia of malignancy. Effective treatment requires cytoreduction of the causative tumour. Denosumab, a RANK ligand inhibitor has proven useful in some cases. ConclusionThis challenging case highlighted the rare but potentially fatal association of pNET with hypercalcemia. Hypercalcemia was the main cause for mortality in an otherwise relatively indolent malignancy.