Endocrine Abstracts

Phaeochromocytomas show a positive correlation between tumour size, metanephrines level and symptoms. Small tumours (<1 cm) are usually asymptomatic and are picked up through hereditary screening or surveillance of previous tumours. We present a 72-year-old gentleman who was referred to the Endocrinology service with symptoms of palpitations, sweating, dizziness and hypertension for several years. He was investigated for palpitations but no cardiac arrhythmias were present. Plasma metanephrine was mildly elevated at 559 pmol/l (<510 pmol/l). Serial measurement of plasma metanephrine remained mildly raised levels, with highest recorded level of 730 pmol/l. Chromogranin B showed a sequential increase from from 137 pmol/l (<149 pmol/l) to 252 pmol/l. CT adrenals revealed a 9 mm left adrenal nodule with a precontrast attenuation of 19HU, and a relative and absolute washout of 43% and 55% respectively. The nodule showed avid uptake on MIBG scan. In view of these findings, the patient was referred for laparoscopic adrenalectomy which confirmed the presence of a pheochromocytoma. This case shows that a phaeochromocytoma may give rise to troublesome symptoms despite its small size and mildly raised metanephrines. Follow-up with sequential plasma metanephrines and Chromogranin B helped establish the correct diagnosis and treatment for small phaeochromocytoma.