Hibernoma arising from the adrenal gland

Hibernomas, or "brown fat" tumors, arising from the adrenal gland, have not been reported previously. These benign lesions consist of brown fat and demonstrate inert features. The most common anatomic location of these tumors is in the adipose tissue of the thigh, shoulder, chest, and back. We describe a hibernoma within the adrenal gland in close association with a myelolipoma that was excised for its solid enlarging characteristics.