Endocrine Abstracts

Adrenal incidentalomata are a common finding on cross-sectional imaging of the abdomen. Further assessment is required to differentiate benign adrenal masses from adrenocortical carcinomas and hormone-secreting tumours. Phaeochromocytomas are rare catecholamine-secreting tumours arising from chromaffin cells of the adrenal medulla. They classically present with symptoms and signs of catecholamine excess including headache, sweating, hypertension and tachycardia. However, with increased use of abdominal cross-sectional imaging it is becoming more common to discover asymptomatic phaeochromocytoma through assessment of adrenal incidentalomata.

We describe a 63-year-old man presenting with renal colic. Cross-sectional imaging of his renal tract with CT showed a 5 mm stone in the proximal ureter, but also a 40 mm right adrenal mass with indeterminate characteristics (attenuation value of 30–40 HU). He had no symptoms of catecholamine excess, no family history of phaeochromocytoma and was normotensive. Investigations for adrenal hormone excess, including 24-hour urinary metanephrine excretion, were normal. Interval imaging showed a 5 mm increase in maximum diameter over 6-months and a decision was made, based on size change and imaging characteristics, to proceed to a right laparoscopic adrenalectomy.

Surgery proceeded uneventfully without pre-operative alpha adrenoreceptor blockade. In particular intra-operative blood pressure remained stable between 100–170 mmHg systolic and 60–90 mmHg diastolic. Histological examination of the tumour showed appearances typical of phaeochromocytoma.

This report describes a rare case of a patient with an adrenal incidentaloma who underwent adrenalectomy based on radiological size and appearance criteria and in whom post-operative histology demonstrated a phaeochromocytoma despite normal 24-hour metanephrine levels; a non-secretory phaeochromocytoma. It highlights the changing presentation of phaeochromocytoma from classical symptomatic disease to more incidental asymptomatic disease. However, it is very rare to see asymptomatic disease with no biochemical evidence of catecholamine excess.