PTHrP-induced hypercalcemia: a rare and challenging presentation in metastatic pancreatic neuroendocrine tumour
S. Pan1, S. Curran1, P. Corrie2 & H. Simpson1
Author affiliations
1Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; 2Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
Introduction: Hypercalcemia due to parathyroid-hormone-related-peptide (PTHrP) is rare in neuroendocrine tumours.
A 63-year-old lady initially presented to ENT surgeons with symptoms of reflux, dysphagia, and weight loss. Past medical history included hysterectomy eight years previously for uterine prolapse. There was no family history of note. Investigations revealed corrected calcium was elevated at 2.94 (2.1–2.5) mmol/l. ALP: 184 (30–135) U/l. CA19-9 was normal. PTH was suppressed <3 (14–72) ng/l. PTHrP was elevated 4.1 (0–1.8) pmol/l.
CT scan demonstrated an 11×9 cm pancreatic mass arising from the tail of pancreas involving spleen, left kidney, left colon and para-aortic lymph nodes. There were multiple lesions in the liver. EUS guided FNA was performed revealing well differentiated neuroendocrine carcinoma of the pancreas. Subsequent biochemistry revealed chromogranin-A 154 (0–60) pmol/l, Chromogranin B 152 (0–150) pmol/l. Urinary 5-HIAA was normal.
The tumour was locally advanced and surgical resection was not possible. Patient was treated with somatostatin analogues for tumour stasis of NET. Hypercalcemia was treated with intravenous pamidronate but recurred rapidly and was >3 mmol/l 1 week after. Prednisolone 10–15 mg po od was added with no improvement in calcium concentration. Zolendronic acid was administered with a rapid and sustained normalisation of calcium to 2.25 mmol/l.
Conclusions: Hypercalcemia due to parathyroid hormone related-peptide (PTHrP) is rare in neuroendocrine tumours. Managing hypercalcemia was initially challenging however responded to zolendronic acid. Sunitinib is being considered as systemic therapy and it will be interesting to see if calcium concentration falls with use of this agent.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.