Primary Bilateral Macronodular Adrenal Hyperplasia Research Articles

Bilateral adrenalectomy in the 21st century: when to use it for hypercortisolism?

Therapeutic options available for the treatment of Cushing's syndrome (CS) have expanded over the last 5 years. For instance, the efficient management of severe hypercortisolism using a combination of fast-acting steroidogenesis inhibitors has been reported. Recent publications on the long-term efficacy of drugs or radiation techniques have also demonstrated low toxicity. These data should encourage endocrinologists to reconsider the place of bilateral adrenalectomy in patients with ACTH-dependent aetiologies of CS; similarly, the indication of bilateral adrenalectomy is reassessed in primary bilateral macronodular adrenal hyperplasia. The objective of this review is to compare the efficacy and side effects of the various therapeutic options of hypercortisolism with those of bilateral adrenalectomy, in order to better define its indications in the 21st century.

Unilateral Adrenalectomy as a First-Line Treatment of Cushing's Syndrome in Patients With Primary Bilateral Macronodular Adrenal Hyperplasia.

Bilateral adrenalectomy is the reference treatment for Cushing's syndrome (CS) related to primary bilateral macronodular adrenal hyperplasia (PBMAH). It is, however, responsible for definitive adrenal insufficiency. The objective of the study was to evaluate the clinical interest of unilateral adrenalectomy (UA) of the larger gland for the treatment of CS related to PBMAH. This was a retrospective study in four tertiary French centers including all 15 patients with PBMAH and CS who underwent UA of the larger gland between 2001 and 2015. Urinary free cortisol, plasma cortisol, ACTH, body mass index, blood pressure, plasma glucose, and lipids were registered pre- and postoperatively and on follow-up. Median follow-up was 60 months (interquartile range 39-105), including 8 of 15 patients followed up for at least 5 years. A normal or low urinary free cortisol was obtained in 15 of 15 patients (100%) postoperatively. Six patients (40%) became adrenal insufficient, of whom three of six recovered a quantitatively normal cortisol secretion on follow-up. Decrease of both body mass index and blood pressure were observed at 1 year, and decrease of blood pressure was persistent 5 years postoperatively. Diabetes was cured in four of six patients. Two patients experienced a recurrence of hypercortisolism, and one was treated with mitotane, whereas the other underwent a second adrenal surgery 9 years after initial UA. UA induced remission of hypercortisolism in all patients, with sustained significant clinical improvement. The rates of both definitive adrenal insufficiency and 5-year recurrence were low. UA appears an interesting alternative to bilateral adrenalectomy as a first-line treatment in PBMAH responsible for overt CS.

ARMC5 mutation analysis in patients with primary aldosteronism and bilateral adrenal lesions.

Idiopathic hyperaldosteronism (IHA) due to bilateral adrenal hyperplasia is the most common subtype of primary aldosteronism (PA). The pathogenesis of IHA is still unknown, but the bilateral disease suggests a potential predisposing genetic alteration. Heterozygous germline mutations of armadillo repeat containing 5 (ARMC5) have been shown to be associated with hypercortisolism due to sporadic primary bilateral macronodular adrenal hyperplasia and are also observed in African-American PA patients. We investigated the presence of germline ARMC5 mutations in a group of PA patients who had bilateral computed tomography-detectable adrenal alterations. We sequenced the entire coding region of ARMC5 and all intron/exon boundaries in 39 patients (37 Caucasians and 2 black Africans) with confirmed PA (8 unilateral, 27 bilateral and 4 undetermined subtype) and bilateral adrenal lesions. We identified 11 common variants, 5 rare variants with a minor allele frequency <1% and 2 new variants not previously reported in public databases. We did not detect by in silico analysis any ARMC5 sequence variations that were predicted to alter protein function. In conclusion, ARMC5 mutations are not present in a fairly large series of Caucasian patients with PA associated to bilateral adrenal disease. Further studies are required to definitively clarify the role of ARMC5 in the pathogenesis of adrenal nodules and aldosterone excess in patients with PA.

Genetics of primary bilateral macronodular adrenal hyperplasia: a model for early diagnosis of Cushing's syndrome?

Long-term consequences of cortisol excess are frequent despite appropriate treatment after cure of Cushing's syndrome. This might be due to diagnostic delay, often difficult to reduce in rare diseases. The identification of a genetic predisposing factor might help to improve early diagnosis by familial screening. Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a rare cause of Cushing's syndrome. Hypercortisolism in PBMAH is most often diagnosed between the fifth and sixth decades of life. The bilateral nature of the adrenocortical tumors and the occurrence of rare clear familial forms suggest a genetic origin. Indeed, a limited subset of PBMAH can be observed as part of multiple tumors syndromes due to alterations of the APC, Menin or Fumarate Hydratase genes. Rare variants of the phosphodiesterases PDE11A have been associated with PBMAH. The recent identification of ARMC5 germline alterations in 25-50% of PBMAH patients without obvious familial history or associated tumors opens new perspectives. ARMC5 alterations follow the model of a tumor suppressor gene: a first germline inactivating mutation of this 16p located gene is followed by a somatic secondary hit on the other allele (inactivating mutation or allelic loss). Functional studies demonstrate that ARMC5 controls apoptosis and steroid synthesis. The phenotype of index cases patients with the mutation seems more severe than the one of WT index cases. However, phenotype variability within a family is often observed. This review summarizes the genetics of PBMAH, focusing on ARMC5, which offer new perspectives for early diagnosis of Cushing's syndrome.

Uso del muestreo venoso adrenal en un paciente con un síndrome de Cushing adrenal

La hiperplasia macro nodular bilateral o hiperplasia adrenal nodular bilateral independiente de la hormona adrenocorticotrópica es una de las causas menos frecuentes de hipercortisolismo, su diagnóstico supone un reto y no se tiene claridad de cuál es la mejor aproximación terapéutica. El muestreo venoso adrenal que frecuentemente se utiliza para hacer la distinción del sitio de producción hormonal en el hiperaldosteronismo primario podría ser una herramienta útil en este contexto ya que podría brindar información que pudiera guiar el tratamiento. Presentamos el caso de una paciente con síndrome de Cushing ACTH independiente en quien el uso del muestreo venoso adrenal con algunas modificaciones cambio de manera radical el tratamiento y permitió confirmar una hiperplasia adrenal macro nodular.

Novel Insights into the Genetics and Pathophysiology of Adrenocortical Tumors.

Adrenocortical tumors (ACTs) are typically unilateral and can be classified as benign adrenocortical adenomas (ACAs) or malignant adrenocortical cancers (ACCs). In rare cases, tumors may occur in both adrenal glands as micronodular hyperplasia (primary pigmented nodular adrenal dysplasia) or as macronodular hyperplasia (primary bilateral macronodular adrenal hyperplasia, PBMAH). The study of certain tumor predisposition syndromes has improved our understanding of sporadic ACTs. Most ACAs are associated with abnormalities of the cAMP signaling pathway, whereas most ACCs are linked to alterations in IGF2, TP53, or the Wnt/βcatenin pathways. Over the past year, single-nucleotide polymorphism array technology and next-generation sequencing have identified novel genetic alterations in ACTs that shed new light on the molecular mechanisms of oncogenesis. Among these are somatic mutations of PKA catalytic subunit alpha gene (PRKACA) in ACA, germline, and somatic mutations of armadillo repeat containing 5 gene (ARMC5) in primary bilateral macronodular adrenal hyperplasia and somatic alterations of the E3 ubiquitin ligase gene ZNRF3 in ACC. This review focuses on the recent discoveries and their diagnostic, prognostic, and therapeutic implications.

Functional study of ARMC5 (armadillo repeat containing 5), a new tumour suppressor gene involved in primary bilateral macronodular adrenal hyperplasia

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

ARMC5 Mutations in a Large Cohort of Primary Macronodular Adrenal Hyperplasia: Clinical and Functional Consequences.

Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a rare cause of primary adrenal Cushing's syndrome (CS). ARMC5 germline mutations have been identified recently in PBMAH. To determine the prevalence of ARMC5 mutations and analyze genotype-phenotype correlation in a large cohort of unrelated PBMAH patients with subclinical or clinical CS. ARMC5 was sequenced in 98 unrelated PBMAH index cases. PBMAH was identified by bilateral adrenal nodular enlargement on computed tomography scan. The effect on apoptosis of ARMC5 missense mutants was tested in H295R and HeLa cells. Clinical and hormonal data were collected including midnight and urinary free cortisol levels, ACTH, androgens, renin/aldosterone ratio, cortisol after overnight dexamethasone suppression test, cortisol and 17-hydroxyprogesterone after ACTH 1-24 stimulation and illegitimate receptor responses. Computed tomography and histological reports were analyzed. ARMC5-damaging mutations were identified in 24 patients (26%). The missense mutants and the p.F700del deletion were unable to induce apoptosis in both H295R and HeLa cell lines, unlike the wild-type gene. ARMC5-mutated patients showed an overt CS more frequently, compared to wild-type patients: lower ACTH, higher midnight plasma cortisol, urinary free cortisol, and cortisol after dexamethasone suppression test (P = .003, .019, .006, and <.001, respectively). Adrenals of patients with mutations were bigger and had a higher number of nodules (P = .001 and <.001, respectively). ARMC5 germline mutations are common in PBMAH. Index cases of mutation carriers show a more severe hypercortisolism and larger adrenals. ARMC5 genotyping may help to identify clinical forms of PBMAH better and may also allow earlier diagnosis of this disease.

Primary bilateral macronodular adrenal hyperplasia.

Primary bilateral macronodular adrenal hyperplasia is a rare cause of Cushing's syndrome and is more often diagnosed as bilateral adrenal incidentalomas with subclinical cortisol production. We summarize the recent insights concerning its epidemiology, diagnosis, genetics, pathophysiology, and therapeutic options. Recent publications have modified our notions on the genetics and pathophysiology of bilateral macronodular adrenal hyperplasia. Combined germline and somatic mutations of armadillo repeat containing 5 gene were identified in familial cases, in approximately 50% of apparently sporadic cases and in the relatives of index cases; genetic testing should allow early diagnosis in the near future. The recent finding of ectopic adrenocortical production of adrenocorticotropic hormone in clusters of bilateral macronodular adrenal hyperplasia tissues and its regulation by aberrant hormone receptors opens new horizons for eventual medical therapy using melanocortin-2 receptor and G-protein-coupled receptor antagonists. Finally, some medical and surgical treatments have been updated. Recent findings indicate that bilateral macronodular adrenal hyperplasia is more frequently genetically determined than previously believed. Considering the role of paracrine adrenocorticotropic hormone production on cortisol secretion, the previous nomenclature of adrenocorticotropic hormone-independent macronodular adrenal hyperplasia appears inappropriate, and this disease should now be named primary bilateral macronodular adrenal hyperplasia.