Combined primary aldosteronism and preclinical Cushing's syndrome due to a large adrenocortical adenoma
Jasmina Ciric, Biljana Beleslin, Mirjana Stojkovic, Bozo Trbojevic & Milos Zarkovic
The rarest causes of primary aldosteronism are aldosterone producing carcinoma, ectopic aldosterone secretion and familial aldosteronism. There are also few cases reported of aldosterone and cortisol tumor cosecretion. We present a 38-year-old woman admitted to our hospital because of resistant hypertension, large adrenal tumor and hypokalemia. At age 32 hypertension was diagnosed, but routine laboratory and abdominal ultrasound examination were normal. Few months before admission, hypokalemia was registered and abdominal CT showed left adrenal adenoma of 6 cm in diameter. Endocrinological tests revealed high upright plasma aldosterone level (1380 ng/l) and low plasma renin activity (0.7 ng/ml per h) suppressed by 2 l of saline infusion to 160 ng/l and <0.2 ng/ml per h, respectively. Supine aldosterone level was 156 ng/l and plasma renin activity <0.2 ng/ml per h. Morning cortisol level was not suppressed by 1 mg (259 nmol/l), or 8 mg (337 nmol/l) of dexamethasone. ACTH level was low, 3.5 pmol/l. After high dose dexamethasone, a stimulation with 250 μg of ACTH was performed and a sharp increase of aldosterone from 376 to >1380 ng/l was detected, as well as an increase of cortisol to 1286 nmol/l. Plasma DHEAS level was low. Left adrenalectomy was done and a tumor of yellow cut surface was found. It was a benign cotical adenoma mostly consisting of light clear cells. Normal adrenal gland tissue was atrophic. On the bases of endocrinological testing this rare case of combined aldosterone and cortisol tumor secretion demonstrated that although autonomous, aldosterone secretion could be both ACTH and angiotensin dependant.