The authors present the case histories of 2 siblings with the virilizing form of congenital adrenal hyperplasia (CYP21 deficiency). The diagnosis was established during the neonatal period; however, glucocorticoid therapy was inconsistent. At the age of 30, the first case presented with pain in the right upper quadrant. An ultrasound scan disclosed a large mass occupying the greater part of the abdominal cavity. On computed tomography, this mass showed characteristics compatible with myelolipoma. The diagnosis was confirmed by pathologic examination. Interestingly, the sister of this patient, who was asymptomatic, was found to have similar tumors on both adrenal glands by ultrasound examination. The pathologic examination of these tumors confirmed the diagnosis of myelolipoma. The precise mechanism of myelolipoma development is not known. Prolonged ACTH stimulation could be a contributing factor. Both patients are now being treated with glucocorticoids. A review of the literature is presented.