Adrenal Myelolipoma

Axial CT image shows a large right adrenal mass (arrows) which contains several foci of macroscopic fat (arrowhead).

Facts:

• Benign biochemically inactive tumor of the adrenal gland thought to be due to metaplastic change of reticuloendothelial system of capillaries
• Contains mature adipose tissue and normal hematopoietic cells
• Most commonly occurs in adrenal glands, but can be seen in other tissues (ie, retroperitoneum presacral region)
• Most are asymptomatic (found incidentally on imaging). If large, or symptomatic, it can be treated with surgical excision and/or adrenalectomy
• Rare, less than 0.2% in population

Imaging Features

• Adrenal mass containing fat attenuation, virtually diagnostic of adrenal myelolipoma (bright on ultrasound, fat on CT and MR)
• May contain calcification

Reference:

Adrenal myeloliopma at URL: http://path.upmc.edu/cases/case165/dx.html