Endocrine Abstracts

Paragangliomas are rare neuroendocrine tumours arising from the extra-adrenal autonomic paraganglia. Clinical presentation is usually related to catecholamine hypersecretion. Hypercalcaemia is rarely reported and the aetiology is varied. Literature review revealed two cases of PTHrP-related and one calcitonin-related hypercalcaemia. No prior reports were found of avascular necrosis with paraganglioma. A 69-year-old female presented with severe constipation, weight loss, anorexia and lethargy. She had a background of progressive metastatic noradrenaline-secreting paraganglioma since 2013. Despite two surgical resections and iodine meta-iodobenzylguanidine (MIBG) therapy she had significant progression of disease. Genetic screening was negative. Her corrected calcium was 3.12 mmol/l (2.2 ×2.6), phosphate 0.95 mmol/l (0.8×1.5), 25-vitamin D 95 nmol/l (>50 nmol/l). Renal function was normal. Parathyroid hormone was suppressed; 12 ng/l (10×47 ng/l), her calcitonin was 1.4 ng/l (<10), her PTHrP was 5.24 pmol/l (<1.4). MIBG and CT imaging revealed metastases involving multiple lymph nodes, liver, peritoneum and retroperitoneum but no skeletal metastases. Plasma normetanephrines were >80,000 pmol/l (0-1180), metanephrines 537 pmol/l (0-510) and 3-methoxytyramine 2030 pmol/l (0-180). Isotope bone scan showed increased uptake in humeral heads and proximal femurs in keeping with avascular necrosis.She received intravenous fluid therapy and two doses of zolendronic acid. There was an initial treatment response (corr Ca 2.9 mmol/l). However, after a few days her calcium rose again (3.29mmol/l). Unfortunately, her condition deteriorated and she passed away.This case highlights paragangliomas secrete non-catecholamine products like PTHrP and can cause hypercalcaemia. This is the first reported case of avascular necrosis associated with paraganglioma.