Endocrine Abstracts

Cardiac phaeochromocytomas account for only 1% of all extra-adrenal phaeochromocytomas. We present a rare case, which through a multidisciplinary approach achieved an excellent outcome. A 49-year-old male presented with chest pain. Echocardiography revealed a pericardial mass behind the left atrium and subsequent cardiac angiography confirmed a highly vascular lesion, suspicious for a phaeochromocytoma. Urine and plasma metanephrines were elevated; urine normetadrenaline 10888 nmol/24 h (0-3350), urine 3-methoxytyramine 15716 nmol/24 h (0–2750) and urine metadrenaline 746 nmol/24 h (0–1250). Plasma normetadrenaline 11648 pmol/l (120–1180 pmol/l), metadrenaline 370 pmol/l (80–510 pmol/l), 3-methoxytyramine 4575 pmol/l (0–120 pmol/l) . There was no family history of endocrine disease and no stigmata of MEN or neurofibromatosis but retrospectively the patient gave a two year history of intermittent headache, palpitations and nausea. The 48x35x38mm soft tissue mass posterior to the left atrium was MIBG-avid, 68Ga-DOTATATE-PET showed no adrenal or other extra-adrenal disease. A diagnosis of cardiac phaeochromocytoma was made and the patient commenced oral Phenoxybenzamine including pre-operative in-patient uptitration. The tumour was removed in a two-stage procedure with coiling and embolization of feeder vessels under Phenoxybenzamine blockade followed by conversion to reversible alpha blockade using Doxazosin 4 mg bd in preparation for tumour resection on cardiopulmonary bypass. The patient underwent successful tumour resection seven months after presentation and histology confirmed a phaeochromocytoma with complete excision, staining positive for chromogranin and synaptophysin. Due to his young age and rare presentation genetic testing revealed a SDHC germline mutation and he was referred for genetic counselling. Approximately one third of phaeochromocytomas are due to germline mutations with over twenty-one genes implicated. SDHC mutations are usually associated with head and neck paraganglioma or phaeochromocytomas with noradrenaline, dopamine or silent hormonal profile and low malignancy risk. Our patient remains well though will remain under lifelong endocrine follow up.