BACKGROUND: Primary bilateral macronodular adrenocortical hyperplasia (PBMAH) is a highly heterogeneous disease with divergent manifestations ranging from asymptomatic subclinical Cushing syndrome (CS) to overt Cushing syndrome with severe complications. ARMC5 mutations occur in 20 to 55% PBMAH patients usually with more severe phenotypes. Different ARMC5 mutations might be associated with diverse phenotypes of PBMAH.

CASE PRESENTATION: A 39-year-old man was admitted to our hospital with progressive weight gain and severe hypertension. He presented typical CS and its classical metabolic and bone complications like hypertension and osteoporosis. The laboratory results showed high levels of cortisol and low levels of ACTH. Low- and high-dosed dexamethasone suppression tests were negative. Contrast-enhanced computed tomography (CT) revealed multiple bilateral irregular macronodular adrenal masses. Adrenal venous sampling (AVS) confirmed that the right adrenal gland with larger nodules secreted more hormone that the left side did. Right adrenalectomy and subsequent contralateral subtotal resection were conducted. His blood pressure and CS symptoms as well as comorbidities including backache and muscle weakness improved. Whole exome sequencing identified one ARMC5 germline mutation (c.1855C > T, p. R619*), five ARMC5 somatic mutations (four novel mutations) in his right and left adrenal nodules.

CONCLUSIONS: This PBMAH patient was identified with one ARMC5 germline mutation and five different somatic ARMC5 mutations (four novel mutations) in the different nodules of the bilateral adrenal masses. AVS combined with CT imagine could be helpful to determine the dominant side for adrenalectomy. Genetic testing is important for the diagnosis and management of the patient with PBMAH.