Clinical Presentation

A newborn with prenatal hydronephrosis.

(A) Longitudinal gray-scale ultrasound (US) image: superior to the normal-appearing kidney is a large, predominately hypoechoic mass with a peripheral hyperechoic rim and internal debris (arrow). (B) Doppler US image: there is no blood flow within the lesion (arrow).

Differential Diagnosis

• Adrenal hemorrhage: An avascular mass in the adrenal bed with a mixed echotexture is consistent with hemorrhage.

• Neuroblastoma: Doppler US should show internal blood flow.

• Congenital adrenal hyperplasia: