A novel pathogenic variant of ARMC5 in a patient with primary bilateral macronodular adrenal hyperplasia: a case report

The mutational landscape of ARMC5 in Primary Bilateral Macronodular Adrenal Hyperplasia: an update

BACKGROUND

Primary Bilateral Macronodular Adrenal Hyperplasia (PBMAH) is a rare cause of Cushing's syndrome due to bilateral adrenocortical macronodules. Germline inactivating variants of the tumor suppressor gene ARMC5 are responsible for 20-25% of apparently sporadic PBMAH cases and 80% of familial presentations. ARMC5 screening is now routinely performed for PBMAH patients and families. Based on literature review and own observation, this study aims to give an overview of both published and unpublished ARMC5 genetic alterations and to compile the available evidence to discriminate pathogenic from benign variants.

RESULTS

146 different germline variants (110 previously published and 36 novel) are identified, including 46% missense substitutions, 45% truncating variants, 3% affecting splice sites, 4% in-frame variants and 2% large deletions. In addition to the germline events, somatic 16p loss-of-heterozygosity and 104 different somatic events are described. The pathogenicity of ARMC5 variants is established on the basis of their frequency in the general population, in silico predictions, familial segregation and tumor DNA sequencing.

CONCLUSIONS

This is the first extensive review of ARMC5 pathogenic variants. It shows that they are spread on the whole coding sequence. This is a valuable resource for genetic investigations of PBMAH and will help the interpretation of new missense substitutions that are continuously identified.

Primary bilateral macronodular adrenal hyperplasia: A rare case report of Cushing syndrome and review of literature

RATIONALE

Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a rare cause of ACTH-independent Cushing syndrome (CS), accounting for <2% of CS cases. Diagnosing PBMAH can be difficult and challenging for clinicians.

PATIENT CONCERNS

We report a 52-year-old female, a patient with a history of intermittent fever for 3 years. She presented with nausea, headache, and dizziness for several days, along with fatigue, myalgia, muscle weakness, exertional dyspnea, hoarseness, spontaneous bruising over the past several months, and long-term psychological complaints. Additionally, we observed periorbital and facial edema, right lower quadrant tenderness, and abdominal striae during the examination.

DIAGNOSES

Her laboratory results showed increased cortisol and suppressed ACTH, and an abdominal CT scan revealed 2 heterogeneous masses in the adrenal glands. These findings led us to the diagnosis of PBMAH in this patient. The existence of aberrant receptors was evaluated, and the tests were negative.

INTERVENTIONS

The patient underwent left adrenalectomy and corticosteroid therapy after the surgery. Her clinical complaints improved after the surgery.

OUTCOMES

However, her dependency on corticosteroids was not transient after unilateral adrenalectomy, and she still needs glucocorticoid supplementation 1 year after surgery.

LESSONS

This patient is a case of PBMAH who presented with fever and CS symptoms and underwent unilateral adrenalectomy. Interestingly, she had suppressed cortisol levels for at least 1 year after the unilateral adrenalectomy. Therefore, we suggest further research on the most effective treatment strategies for PBMAH.

Adrenal Lesions: A Review of Imaging

Adrenal lesions are frequently incidentally diagnosed during investigations for other clinical conditions. Despite being usually benign, nonfunctioning, and silent, they can occasionally cause discomfort or be responsible for various clinical conditions due to hormonal dysregulation; therefore, their characterization is of paramount importance for establishing the best therapeutic strategy. Imaging techniques such as ultrasound, computed tomography, magnetic resonance, and PET-TC, providing anatomical and functional information, play a central role in the diagnostic workup, allowing clinicians and surgeons to choose the optimal lesion management. This review aims at providing an overview of the most encountered adrenal lesions, both benign and malignant, including describing their imaging characteristics.