Spontaneous resolution of antenatally diagnosed adrenal masses.

Four infants had adrenal masses detected prenatally, through ultrasonography, between 18 and 30 weeks' gestation. Two were predominantly cystic, and two were solid. The sizes ranged from 0.8 to 1.5 cm. There were no associated prenatal maternal complications or stress factors. The urine vanillylmandelic acid levels at birth were normal in three infants. Two infants had a documented decrease in mass size at birth (compared with the last intrauterine study). All masses had a progressive decrease in size after birth, and ultrasound results were normal at 6 to 12 weeks of age. All four patients are well, with normal study results, at 2 to 5 years of age.