Primary unilateral macronodular adrenal hyperplasia with concomitant glucocorticoid and androgen excess and KDM1A inactivation

Abstract

Background: Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a rare cause of Cushing's syndrome. Individuals with PBMAH and glucose-dependent insulinotropic polypeptide (GIP)-dependent Cushing's syndrome due to ectopic expression of the GIP receptor (GIPR) typically harbor inactivating KDM1A sequence variants. Primary unilateral macronodular adrenal hyperplasia (PUMAH) with concomitant glucocorticoid and androgen excess has never been encountered or studied.

Methods: We investigated a woman with a large, heterogeneous adrenal mass and severe adrenocorticotropic hormone-independent glucocorticoid and androgen excess, a biochemical presentation typically suggestive of adrenocortical carcinoma. The patient presented during pregnancy (22nd week of gestation) and reported an 18-month history of oligomenorrhea, hirsutism, and weight gain. We undertook an exploratory study with detailed histopathological and genetic analysis of the resected adrenal mass and leukocyte DNA collected from the patient and her parents.

Results: Histopathology revealed benign macronodular adrenal hyperplasia. Imaging showed a persistently normal contralateral adrenal gland. Whole-exome sequencing of 4 representative nodules detected KDM1A germline variants, benign NM_001009999.3:c.136G > A:p.G46S, and likely pathogenic NM_001009999.3:exon6:c.865_866del:p.R289Dfs*7. Copy number variation analysis demonstrated an additional somatic loss of the KDM1A wild-type allele on chromosome 1p36.12 in all nodules. RNA sequencing of a representative nodule showed low/absent KDM1A expression and increased GIPR expression compared with 52 unilateral sporadic adenomas and 4 normal adrenal glands. Luteinizing hormone/chorionic gonadotropin receptor expression was normal. Sanger sequencing confirmed heterozygous KDM1A variants in both parents (father: p.R289Dfs*7 and mother: p.G46S) who showed no clinical features suggestive of glucocorticoid or androgen excess.

Conclusions: We investigated the first PUMAH associated with severe Cushing's syndrome and concomitant androgen excess, suggesting pathogenic mechanisms involving KDM1A.

Keywords: KDM1A; MC2R; Cushing's syndrome; GIP receptor; PBMAH; PUMAH; adrenocortical tumor; androgen excess.

Figure 1.

Representation of urine steroid metabolomics, imaging, and histopathological studies. A) A heatmap showing the patient's 24-h urine steroid metabolite excretion measured longitudinally by GC–MS at presentation and during further follow-up as compared to a reference range derived from 24-h urine samples collected by 73 healthy, nonpregnant women. Six urinary steroid metabolites typically found increased in patients with ACC are highlighted by red arrows. B) A magnetic resonance imaging (MRI) scan (T1, left; T1 with contrast, right) of the abdomen shows the right adrenal mass and normal left gland. C) A staging CT scan shows the heterogeneous right adrenal mass. No other lesions elsewhere were detected. D) and E) Coalescent hyperplastic nodules composed of foamy–clear and eosinophilic cells with foci of myelolipomatous metaplasia (D, hematoxylin–eosin 12.5×) and internodular relatively atrophic changes (E, reticulin staining 12.5×).

Figure 2.

KDM1A alterations at genetic and transcriptomic analyses of representative adrenal nodules. A) An IGV visualization of the KDM1A:NM_001009999.3:c.136G>A:p.G46S and KDM1A:NM_001009999.3:exon6:c.865_866del:p.R289Dfs*7 germline variants in blood (DNA_B) and all 4 nodules (DNA_T1-T4). B) A lollipop plot showing the location of the KDM1A germline mutations on a linear KDM1A protein and its domains. C) A visualization of the log2-transformed normalized copy number (cn) profile for all nodules on chromosome1. The normal copy number status is depicted in green; copy number loss is depicted in blue. The position of the gene KDM1A is marked by the dashed gray line. D) An investigation of KDM1A and GIPR expression by transcriptome sequencing in 26 CS-cortisol-producing adenoma (CS-CPAs), 17 adenomas with mild autonomous cortisol secretion (MACS-CPAs), 9 endocrine-inactive adenomas (EIAs), 4 NAGs, and nodule 4 of the patient (PrAC11), respectively.

Figure 3.

RNA-seq (transcriptome) data showing mRNA expression levels of selected relevant genes (ADRB1, AGTR1, AVPR1a, GCGR, GNRHR, HTR4, KISS1R, and LHCGR) in one of the representative nodules (T4) and an available dataset from ACAs, including 43 cortisol-producing adenomas (CPAs, 26 associated with overt Cushing’s syndrome, CS-CPAs, and 17 with mild autonomous cortisol secretion, MACS-CPAs), 9 endocrine-inactive adenomas (EIAs), and 4 NAGs.