Prevalence and phenotype of primary bilateral macronodular adrenal hyperplasia with autonomous cortisol secretion: a study of 98 patients

Prevalence and clinical features of armadillo repeat-containing 5 mutations carriers in a single center cohort of patients with bilateral adrenal incidentalomas

OBJECTIVE

We aimed to evaluate the prevalence of armadillo repeat-containing 5 (ARMC5) genetic defects in our cohort of bilateral adrenal incidentaloma (BAI) patients and to evaluate the possible existence of genotype-phenotype correlations.

DESIGN

Cross-sectional study.

SETTING

Tertiary care center.

PARTICIPANTS

72 BAI patients.

MAIN OUTCOME MEASURE(S)

The following data have been collected: morning adrenocorticotropic hormone (ACTH) concentrations; cortisol levels after 1 mg overnight dexamethasone suppression test (F-1mgDST); urinary free cortisol (UFC) levels; diameter of the adrenal masses; and the association with overweight/obesity, arterial hypertension, diabetes mellitus, dyslipidemia, cardiovascular events, unrelated neoplasia, osteoporosis, thyroid nodular disease, and primary hyperparathyroidism. A search for ARMC5 germline and somatic pathogenic variants was performed in all patients and in the adrenal tissue of patients operated on, respectively.

RESULTS

The prevalence of germline ARMC5 pathogenic variants among patients with mild autonomous cortisol secretion (MACS+, defined as F-1mgDST > 1.8 µg/dL) was 18.8%. No germline pathogenic variants were detected in patients without MACS. Moreover, somatic ARMC5 pathogenic variants were also found in the adrenal tissue of six patients without germline ARMC5 variants. The F-1mgDST levels >5 µg/dL predicted with a poor sensitivity but a 90.5% specificity in identifying the presence of ARMC5 germline pathogenic variants. We did not find any clinical parameter predictive of the ARMC5 mutation presence.

CONCLUSIONS

In MACS+ BAI patients, germline ARMC5 gene pathogenic variants are frequent. Further studies are needed to elucidate the pathophysiological role of somatic ARMC5 pathogenic variants on adrenal tumor development in otherwise wild-type (WT) patients.

Cushing´s syndrome due to bilateral adrenal cortical disease: Bilateral macronodular adrenal cortical disease and bilateral micronodular adrenal cortical disease

Cushing´s syndrome (CS) secondary to bilateral adrenal cortical disease may be caused by bilateral macronodular adrenal cortical disease (BMACD) or by bilateral micronodular adrenal cortical disease (miBACD). The size of adrenal nodules is a key factor for the differentiation between these two entities (>1cm, BMACD and <1cm; miBACD). BMACD can be associated with overt CS, but more commonly it presents with autonomous cortisol secretion (ACS). Surgical treatment of BMACD presenting with CS or with ACS and associated cardiometabolic comorbidities should be the resection of the largest adrenal gland, since it leads to hypercortisolism remission in up to 95% of the cases. Medical treatment focused on the blockade of aberrant receptors may lead to hypercortisolism control, although cortisol response is frequently transient. miBACD is mainly divided in primary pigmented nodular adrenocortical disease (PPNAD) and isolated micronodular adrenocortical disease (i-MAD). miBACD can present at an early age, representing one of the main causes of CS at a young age. The high-dose dexamethasone suppression test can be useful in identifying a paradoxical increase in 24h-urinary free cortisol, that is a quite specific in PPNAD. Bilateral adrenalectomy is generally the treatment of choice in patients with overt CS in miBACD, but unilateral adrenalectomy could be considered in cases with asymmetric disease and mild hypercortisolism. This article will discuss the clinical presentation, genetic background, hormonal and imaging features and treatment of the main causes of primary bilateral adrenal hyperplasia associated with hypercortisolism.