ACTH-Independent Cushing’s Syndrome Associated with Left Adrenocortical Oncocytoma of Uncertain Malignant Potential

Table 1

Laboratory tests.

		Before hospitalization	First visit	Overnight suppression test	2 days postsurgery	A month later surgery	Normal range
Plasma sodium	mEq/L	146	143		137	141	136–145
Plasma potassium	mEq/L	5.10	4.30		4.50	4.50	3.50–5.10
Plasma basal cortisol	μg/dl	28.4	21.40	19.90	1.10	0.9	4.4–22.0
Plasma ACTH	pg/ml	<5	<5		<5	<5	0.0–46.00
24 h urinary free cortisol	mcg/24 h	434.70	356.4		2.5		0–100
24 h urinary sodium	mMol/24 h	78.30	250.80				40–220
24 h urinary potassium	mMol/24 h	75.60	132.00				25–125

Laboratory tests are conducted to determine the etiology of Cushing’s syndrome showed modest increase in basal cortisol with abolition of its circadian rhythm and ACTH levels constantly and markedly suppressed. Bold values represent lab tests out of range and the ones useful in diagnosing ATCH-independent Cushing's syndrome.