The case of a left adrenal mass detected by ultrasonography in a male fetus at the 37th week of gestation is presented. After an uneventful delivery at the 38th gw, the newborn was sonographically monitored, and during the follow-up clinical evaluations were performed, in order to make a differential diagnosis between an adrenal hemorrhage and a congenital neuroblastoma. VMA and HVA were within normal levels, and MIGB scan was negative. A MR of the the abdomen performed at the age of one month was suggestive for an adrenal hemorrhage in involution. We therefore decided to keep monitoring the mass by ultrasound, avoiding any surgical approach. The sonographic complete disappearance of the disease was documented at the end of the fourth month.