Endocrine Abstracts

Incidentally discovered adrenal masses on abdominal imaging for unrelated reasons have a prevalence of 1-7%. A great majority of these are non-functioning adenomas, but 5-30% are associated with autonomous cortisol secretion (ACS), which is mainly subclinical, and 1-5% with phaeochromocytoma or Conn’s syndrome. Here we report two cases of overt functioning adrenal adenoma with coexisting ACS. We could not find any other reports of such cases in the literature.

Case 1: A 38-year lady presenting with pain abdomen, hot flushes and palpitations. Her blood pressure was 133/88 mmHg. CT abdomen showed a well-circumscribed large left adrenal solid mass (74x63x62mm) with cystic components. Her 24hr-urine metadrenaline (5.25 micromol/24h (NR:0-1.2)) and normetadrenaline (140 micromol/24hr (NR:0-3.3)) were high; genetic test was negative. Her cortisol was not suppressed on overnight dexamethasone suppression test (360nmol/l), and low-dose dexamethasone suppression test (315nmol/l)); her aldosterone-renin ratio was normal. Of note, she did not have diabetes, or Cushingoid features. She had left adrenalectomy with peri- and post-operative steroid support. Histopathology confirmed phaeochromocytoma with low proliferation index. She failed the short-synacthen test at two weeks (30-min cortisol: 295nmol/l), but passed it two months later.

Case 2: A 55-year man with hypertension and hypokalaemia with a high aldosterone-renin ratio (530 pmol/l, < 0.2 nmol/l/hr) -- off Ramipril and normal potassium -- suggesting Conn’s syndrome. His 24-hour urine cortisol was high (244 nmol/24hr), and serum cortisol (82 nmol/l) was not suppressed on low-dose dexamethasone suppression test; 24hr-urine metanephrines were normal. He had no Cushingoid features or diabetes. CT abdomen showed a 2.5 cm left adrenal adenoma (< 10HF units) and normal right adrenal. He is awaiting surgery. These two very rare cases show the need for looking for autonomous cortisol secretion in other overt functioning adrenal adenoma as the former would need peri- and postoperative stress glucocorticoid support.