Imaging diagnosis--bilateral adrenal adenomas and myelolipomas in a dog.

A 10-year-old neutered female Pug was evaluated for a left adrenal mass detected previously by ultrasonography. Using computed tomography, a fat-attenuating, rim-enhancing left adrenal mass and a homogeneous, soft-tissue attenuating, intensely enhancing right adrenal mass were found. A left adrenalectomy and right adrenal biopsy were performed and the final diagnosis was bilateral adrenal adenomas and myelolipomas. Myelolipomas are rare, benign, endocrinologically inactive tumors composed of well-differentiated adipose tissue and a variable amount of hematopoietic cells of both lymphatic and myeloid lineages, which may account for the different appearance on tomographic images.