Myelolipoma associated with adrenocortical adenoma: an unusual cause of Cushing's syndrome.

Adrenal myelolipoma is a benign, rarely functioning tumor consisting of adipose tissue and myeloid cells in different proportions. Adrenal myelolipoma accounts for approximately 6% of adrenal incidentalomas and is found in up to 0.2% of autopsy studies. Few cases of myelolipomatous masses causing Cushing’s syndrome (CS) have been reported in the literature, so that the functioning capacity that these tumors may sometimes have can easily be overlooked. The case of a patient with clinically evident CS in whom imaging tests disclosed an adrenal myelolipoma is reported below. This was a 36-year-old male with diabetes who attended our hospital for blood glucose monitoring. The patient had been diagnosed 10 years before with metabolic syndrome with high blood pressure, type 2 diabetes, dyslipidemia, and obesity. The course of the disease had been unfavorable despite compliance with hygienic and dietary advice and with adequate medication. Physical examination revealed central obesity with a body mass index (BMI) of 38.6 kg/m, waist circumference of 125 cm, blood pressure of arterial 149/109 mmHg, and clinical features of frank CS with facial redness, red-wine abdominal striae, and strong muscle weakness. Basal plasma ACTH levels were suppressed (4.5 pg/mL; normal range [NR] 5--45), while 24-h plasma cortisol levels (15 mcg/dL) and 24-h urinary free cortisol levels (1218 mcg; NR 4.3--176) were both elevated. Plasma cortisol was not suppressed (16 mcg/dL) after administration of dexamethasone 8 mg. Abdominal computed tomography (CT) showed a left adrenal mass 4.5 cm in the longest axis with a fat density component suggesting myelolipoma