Endocrine Abstracts

Introduction: Primary bilateral macronodular adrenal hyperplasia (PBMAH) is an uncommon cause (<1%) of endogenous Cushing’s syndrome (CS). Recently, due to increased number of incidental imaging findings of PBMAH, the clinical expression of the disease has changed in favor of oligosymptomatic or subclinical cases, compared to those with clinically manifest CS, or rarely with secretion of mineralocorticoids, or sex steroids.

Case report: A 51-year-old overweight woman was referred to our Institute for assessment of incidentally diagnosed bilateral macronodular adrenal hyperplasia. She had a history of dyslipidemia, and paroxysmal hypertension. Physical examination revealed no typical signs or symptoms of hormonal hypersecretion, except for a slightly elevated blood pressure (140/90 mmHg). Blood test results revealed normal plasma metanephrines, normmetanephrines, and normal renin aldosterone ratio. Subnormal suppression of serum cortisol following 1-mg overnight dexamethasone suppression test (2.34 µg/dl), 2×2 mg overnight dexamethasone supression test (1.92 µg/dl) and a suppressed ACTH (2.52 pg/ml) were suggestive of ACTH independent subclinical CS. Given that in PBMAH, adrenals may have aberrant receptors that stimulate excess cortisol secretion, we followed a screening protocol, which had positive (> 50% increase of serum cortisol) results for postural, mixed meal tests, and partially positive (> 25% increase of serum cortisol) for diphereline test. In our case, taking into account the patient’s preference, as well as the mild clinical expression of the disease, we recommended active surveilling with yearly imaging and hormonal monitoring.

Conclusion: Considering the increased heterogeneity of PBMAH, due to modern imaging techniques that led to early detection, a clear diagnostic criteria is required in order to better characterize this entity and develop a tailored treatment plan.