Bilateral adrenocortical adenomas causing adrenocorticotropic hormone-independent Cushing’s syndrome: A case report and review of the literature

Table 1 Endocrinological study at different periods of bilateral adrenocortical adenomas

Baseline					Low-dose dexam test	High-dose dexam test
		00:00 h	08:00 h	16:00 h
Before the operation	ACTH (pmol/L)	4.26	4.13	3.62	3.51	4.1
	F (nmol/L)	606.42	761	618.08	579.34	689.18
	UFC (nmol/L)	1650.7	-	-	3073.5	2122.6
After unilateral operation	ACTH (pmol/L)	7.84	7.86	7.7	9.28	-
	F (nmol/L)	391.78	440.08	455.65	414.36	-
	UFC (nmol/L)	1024.9	-	-	1117	-
After bilateral operations	ACTH (pmol/L)	4.66	4.86	3.66	4.93	-
	F (nmol/L)	<25.7	<25.7	<25.7	<25.7	-
	UFC (nmol/L)	-	<25.7	-	-	-

Reference range: ACTH at 8 AM, <10.12 pmol/L; F at 8 AM, 198.7-797.5 nmol/L; 4 PM: 85.3-459.6 nmol/L; 0 AM: 0-165.7 nmol/L; UFC: 98.0-500.1 nmol/24 h; dexam: Dexamethasone; ACTH: Adrenocorticotropic hormone; F: Cortical; UFC: Urine free cortisol.

Table 2 The results of peripheral 1-deamino-8-D-arginine-vasopressin stimulation test

Time	ACTH (pmol/L)	F (nmol/L)
-15 min	6.88	640.24
0 min	6.97	624.03
15 min	6.7	637.87
30 min	6.59	590.82
45 min	6.59	625.47
60 min	7.19	598.56
90 min	7.26	524.71
120 min	6.68	577.39

Normally, adrenocorticotropic hormone (ACTH) peaks between 15 min and 30 min after the infusion of DDAVP, while this patient had delayed peaking. Cushing disease is suspected if the peak level of ACTH is over 1.5 times much more than the baseline level. We can definitely diagnose it as Cushing disease if it is over 3 times. This patient’s ratio was 1.05, therefore it is not Cushing disease[30]. ACTH: Adrenocorticotropic hormone; F: Cortisol.

Table 3 The results of bilateral adrenal vein sampling

	LAV	RAV	L/R	PV
ACTH (pmol/L)	8.50	8.73	/	9.10
F (nmol/L)	11093.75	5746.61	14.86	693.38
ALD (ng/dL)	13.95	8.90	/	5.0
F/ALD	795	645	1.23	/

An AV-to-PV cortisol gradient greater than 6.5 is consistent with a cortisol-secreting adenoma. In our case, the LAV-to-PV cortisol gradient was 16, and the RAV-to-PV cortisol gradient was 8.2. The “aldosterone-corrected” high-side to low-side AV cortisol gradient was 2.3 or greater, consistent with autonomous cortisol secretion predominantly from one adrenal gland; a gradient of 2.0 or less indicates bilateral cortisol hypersecretion. The ratio of L/R of our patient was 1.23, less than 2.0. All of these pieces of evidence indicated that the hypersecretion of cortisol might originate from both adrenal glands[17]. ACTH: Adrenocorticotropic hormone; F: Cortisol; LAV: Left side adrenal vein; RAV: Right side adrenal vein; L/R: (left side adrenal vein cortisol/ left side aldosterone): (right side adrenal vein cortisol/right side aldosterone); PV: Peripheral vein; ALD: Aldosterone; F/ALD: Cortisol/aldosterone.