Studies on excised adrenals from primary aldosteronism patients have found that somatic mutations in KCNJ5 frequently cause excess aldosterone production in the culprit aldosterone-producing adenoma (APA). KCNJ5 mutant APAs were reported to be peculiarly overrepresented among young females and in Oriental cohorts, compared to their older male, or Caucasian counterparts. These larger APAs were also reported to have similarities with the zona fasciculata (ZF) in the adrenal both from the steroid production profile and the morphology of the cell. We therefore aimed to corroborate these findings by characterizing the APAs from a multi-ethnic Malaysian cohort. The prevalence of KCNJ5 mutations was estimated through targeted DNA sequencing of KCNJ5 in 54 APAs. Confirmation of APA sample acquisition was performed by CYP11B2 immunohistochemistry (IHC) staining. The ZF steroid production profile was based on the ZF enzyme CYP17A1 IHC staining, and ZF cell morphology was based on a high cytoplasm to nucleus ratio. Seventeen (31.5%) APAs studied, harbored a KCNJ5 mutation. No female over-representation was seen in this cohort though females were found to have a higher expression of CYP11B2 than males (p = 0.009; Mann-Whitney U test). Age at adrenalectomy correlated negatively with the percentage of ZF-like cells in the APA (p = 0.01; Spearman's rho) but not with the KCNJ5 genotype. KCNJ5 mutant APAs had a high percentage of ZF-like cells (and high CYP17A1 expression) but so did the wild-type APAs. In summary, prevalence of KCNJ5 mutant APAs in this cohort was similar to other Caucasian cohorts, however, over-representation of females did not occur, which is similar to some studies in Oriental cohorts.
Approach to patients who manifest with features of Cushing's syndrome often begin with exclusion of exposure to excessive exogenous source of glucocorticoids (GC). Most guidelines advocate no further assessment if excessive exogenous GC use is present. We present a case of a 66-year-old lady who was noted to have typical features of Cushing's syndrome. As she gave a very clear history of ingesting exogenous GC for a year, no further work up was undertaken. Despite cessation of GC for a year, she continued to have thin skin and easy bruising. Upon admission for hypertensive emergency, her clinician took note of her changes and investigated her for endogenous Cushing's syndrome. Her cortisol post overnight dexamethasone suppression test was 707 nmol/l. Post low dose dexamethasone suppression test yielded a cortisol of 1133.2 nmol/l. 24 hours urine cortisol was 432.2 nmol/l. Plasma ACTH was 1.1 pmol/l, indicating an ACTH independent Cushing's syndrome. We proceeded with Computed tomography scan (CT scan) of adrenals which revealed a right adrenal adenoma measuring 4.4 × 3.4 × 4.0 cm. Right retroperiteneoscopic adrenalectomy was done. Histopathology examination was consistent with adrenal cortical adenoma with foci of myelolipoma. Post adrenalectomy she developed hypocortisolism secondary to contralateral adrenal suppression which lasted up to the present date. Her cutaneous and musculoskeletal manifestations improved substantially. Co-occurrence of endogenous and exogenous Cushing's syndromes is uncommon but should be considered in patients whose Cushingnoid features do not resolve after cessation of exogenous GC.