Figure 4d. Adenoma associated with a myelolipoma in a 64-year-old woman with Cushing syndrome. (a) Axial unenhanced CT scan shows a large left adrenal mass with multiple low-attenuation areas centrally (horizontal arrow) that represent pockets of fat. A speck of calcification (vertical arrow) is also noted adjacent to the fatty component. (b) Contrast-enhanced arterial-phase CT scan shows mild enhancement of the mass. (c) Axial spin-echo T1-weighted MR image (500/16) shows the mass with small central foci of high signal intensity (arrow) that correspond to the foci of fat seen at CT. (d) Axial fast spin-echo T2-weighted MR image (6,000/102) shows the mass with mixed signal intensity. Multiple high-signal-intensity foci of varying size are seen within the mass and correspond to the hematopoietic component of a myelolipoma, which in this case forms a large part of the mass (cf e). (e) Photomicrograph (original magnification, x100; H-E stain) (left) shows a myelolipoma with a capsule (C) superior to adrenocortical tissue (A), the hyperfunctioning part of the lesion. More inferiorly, there is a mixture of vacuolated fat cells (F) and hematopoietic (bone marrow) cells (H), which make up a large part of the myelolipoma. A higher-power photomicrograph of the same lesion (original magnification, x200; H-E stain) (right) demonstrates a vacuolated fat cell (F) surrounded by markedly hyperchromatic hematopoietic cells.