Correlation Between MRI Phenotypes and Cortisol Dynamics in a Cohort of Patients with Adrenal Incidentalomas

Presentation Number: SUN 403
Date of Presentation: April 2nd, 2017

Martha Katherine Huayllas*1, Lilian F. Hayashi2, Kelly C. Oliveira2, Ravinder J. Singh3, Brian Netzel4, Gopi Kiran Sirineni5 and Claudio E. Kater2
1Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil, 2Federal University of São Paulo, São Paulo, SP, Brazil, 3Mayo Clinic, 4Mayo Clinic, Rochester, MN, 5Creighton University, Omaha, NE

Abstract

Introduction: AI may occur in 5% of the adult population. AI should be carefully screened for the possibility of malignancy and steroid overproduction with a specific steroid panel and imaging phenotype. Although most are non-functioning adrenal adenomas (NFA), subclinical hypercortisolism (SCH) may occur in up to 30%. Detection of SCH is key, since multiple cardiovascular risk factors may increase mortality rate. SCH is identifiable with the 1mg dexamethasone suppression test (DST), in which a serum cortisol response >1.8 µg/dl is highly suspect. Other post-DST cutoffs ranging from 2.5 to 5 µg/dl are also employed. Size, appearance and “chemical shift” on MRI are used to define benign lesions. Aim: evaluate the possible correlation between size of the adrenal lesion and cortisol dynamics in patients with an AI. Patients and method: 53 patients with AI (38 unilateral [UAI], 15 bilateral [BAI]; 42-87y [median: 61]; 64% female) were studied at UNIFESP. They were not taking steroids or other drugs that could interfere with cortisol metabolism or measurement. After clinical evaluation, all underwent a dedicated adrenal MRI (Siemens, WG) and had blood samples collected for cortisol (F) in 3 settings: basal, 9h after 1mgDST, and 60 min after ACTH (pACTH). Area and volume of the single (UAI) or the larger of bilateral nodules (BAI) were verified by one of us (GKS). Cortisol was measured by LC/MS-MS at Mayo Laboratories and ACTH, DHEAS, and dexamethasone (Dx) by routine methods at the Endocrine Division in São Paulo. Results: Obesity, hypertension, diabetes, and dyslipidemia were present in 44%, 66%, 34% and 60%. ACTH <10 pg/mL and DHEAS <30 µg/dl were present in 26% and 40%, respectively. Regarding DST, 50% suppressed F below 1.8 and 70% below 2.5 µg/dL. The larger diameter and volume of the lesion on MRI varied from 2.5± 0,9 (1,1 – 5 cm) and 6.5±7.3 (0.4-41.6 cm3), respectively. We found a positive correlation between nodule volume with the degree of pDST F (r= 0.40), and with AC (r= 0.36). No correlation was found with basal or stimulated F, ACTH or DHEAS. Discussion: There is no current protocol to follow up AI with SCH, but it is important to identify SCH under increased cardiovascular risk as they may benefit from specific treatment. The hormonal autonomy of an UAI or BAI can be underestimated if proper tests are not performed, in particular DST. ACTH and specially DHEAS varies with gender and age, but low levels could supplement DST in defining SCH. Conclusion: Post-DST F levels are recommended to recognize SCH among AI, either using the highly sensitive cutoff of 1.8 µg/dl or the more specific 2.5 µg/dl. The positive correlation between the degree of pDST F and the volume of the lesion indicates that the larger the nodule the more autonomous and clinically harmful it is, prompting a favorable decision towards surgical removal to prevent progression of cardiovascular morbidity.

 

Nothing to Disclose: MKH, LFH, KCO, RJS, BN, GKS, CEK