Endocrine Abstracts

Adrenal incidentalomas are tumours of the adrenal incidentally discovered during evaluation for non-adrenal disease. The National Institute of Health consensus definition usually excludes lesions found during evaluation for malignancy. We present a case of an initially non-secretory adrenal incidentaloma that progressively increased in size over 6 years and became hormonally active.

A 78-year-old hypertensive male was found to have a right adrenal mass during investigation for a rectal carcinoma. He underwent a successful anterio-posterior resection requiring no adjuvant therapy. Initial surveillance under the surgeons involved 6 monthly abdominal computed tomograms (CT). Over a 2 year period the mass increased in size from 2 to 3 cm in longest diameter. Neither unenhanced CT nor chemical shift MRI (CSI) was compatible with a benign adenoma. He was therefore referred to endocrinology.

He was asymptomatic and normotensive on amlodipine and doxazosin. Initial hormonal evaluation showed that his cortisol circadian rhythm was preserved, 48 h dexamethasone suppression test suppressed to 59 nmol/l and electrolytes and aldosterone:renin ratio was normal. Urinary catecholamines were not elevated. Over the next 4 years, he remained completely asymptomatic. Follow-up imaging demonstrated a well circumscribed mass that slowly but progressively attained a size of 3.4×2.9 cm with a necrotic centre. There was no loss of signal intensity on CSI. Periodic hormonal evaluation showed normal cortisol, androgens and aldosterone production. At his 6 year follow-up urinary catecholamines and metanephrines were elevated. MIBG showed persistent uptake in the right adrenal. Adrenalectomy was performed and histology confirmed a phaeochromocytoma. Unless there is clear radiological confidence that a benign adenoma is present surveillance and re-assessment of functionality is warranted.