Malignant hypercalcaemia related to parathyroid hormone-related peptide (PTHrP) secretion from a metastatic pancreatic neuroendocrine tumour (NET).

A 54-year-old woman presented to our centre with acute abdominal pain and vomiting. Routine blood tests showed severe hypercalcaemia (>4 mmol/L). Serum parathyroid hormone (PTH) was suppressed. CT scan detected a pancreatic mass and some liver lesions, initially suspicious for metastatic pancreatic adenocarcinoma. Liver biopsy however revealed the presence of a well-differentiated, grade 1, metastatic neuroendocrine tumour (NET) where prognosis is considerably better. Serum PTHrP was raised, indicating paraneoplastic hypercalcaemia, most likely secondary to the pancreatic NET. Following injection of a short-acting somatostatin analogue octreotide, serum PTHrP levels normalised within 24 hours, causing a rapid drop of serum calcium below the lower limit of normal and an immediate compensatory rise of serum PTH. Ongoing treatment with long-acting somatostatin analogues together with replacement with calcium carbonate, vitamin D3 and once weekly alendronic acid resulted in stable normal adjusted calcium levels over a 3-month follow-up period.