Benign hemorrhagic adrenocortical macrocysts in Beckwith-Wiedemann syndrome.

A new pseudotumorous lesion found in the adrenal cortex of six infants with Beckwith-Wiedemann syndrome is described. These cystic masses were discovered either prenatally by using sonography or early in the neonatal period as palpable flank masses. Imaging studies, including sonography and CT, could not confidently exclude malignancy. After the masses were removed surgically, histologic examination showed them all to be benign hemorrhagic macrocysts within the capsule or permanent cortex (in contrast to neonatal adrenal hemorrhage, which usually occurs more centrally in the fetal cortex). The cysts were as large as 8 cm in diameter, and in one case a solitary cyst was predominant. Hemihypertrophy was present in all cases. Four of the six lesions were right-sided, and there was a male-female ratio of 5:1. Benign hemorrhagic adrenocortical macrocysts are a cause of abdominal mass in the fetus and neonate with Beckwith-Wiedemann syndrome.