Endocrine Abstracts

Background: ACTH-Independent Macronodular Adrenal Hyperplasia (AIMAH) is usually manifested as both-sided adrenal incidentalomas with subclinical overproduction of cortisol (<2% of Cushing’s syndrome). The pathogenesis involves genetic factors, expression of adrenal aberrant hormone receptors and paracrine adrenal corticotropin (ACTH) secretion. Treatment is usually bilateral adrenalectomy, but in some cases also unilateral adrenalectomy or pharmacologic therapy can be considered.

Case presentation: Here, we present two cases of AIMAH. 48 year old male suffering from resistant hypertension and 69 year old asymptomatic female with adrenal incidentalomas. Both patients manifested lack of diurnal cortisol rhythm, inhibited ACTH level and no cortisol suppression in 1 and 8 mg dexamethasone test, although 24-h urinary free cortisol was normal. CT revealed 8 lipid-rich bilateral adenomas in man and 3 lipid-rich adenomas in woman. In dynamic tests- upright posture test was positive in two cases, cortisol rise in metoclopramide test and oral glucose tolerance test were detected individually. Whole body octreotide scintigraphy was performed. Unilateral uptake in patient’s adrenals in 131I-norcholesterol scintigraphy (INCS) resulted in one-sided adrenalectomy. Histopathological evaluation of resected adrenal gland in man confirmed AIMAH and his blood pressure dropped after surgery.

Conclusions: AIMAH may be manifested as adrenal incidentalomas with lack of Cushing’s syndrome symptoms. Non-standardized hormonal tests facilitate pharmacotherapy in AIMAH patients. Determination of hyperactive adrenal gland by INCS in case of bilateral adrenal tumors enable to preserve contralateral adrenal gland and avoid permanent adrenal insufficiency. To obtain a wide spectrum of therapeutic possibilities a diagnostic process should cross beyond a routine management.