Purely cystic adrenal lesion in a newborn evolving into a solid neuroblastoma

Purely cystic neuroblatomas are often discovered prenatally. As the main differential diagnosis is adrenal hemorrhage, follow‐up sonography is warranted after birth. Cystic neuroblastomas are expected to evolve into lesions of mixed echogenicity with cystic and solid components. We present a rare case of a purely cystic left‐sided adrenal lesion in a newborn, suggesting an adrenal hemorrhage, which on follow‐up sonography evolved into a purely solid mass with poor vascularization, diagnosed as a cystic neuroblastoma. We suggest that even purely cystic adrenal masses in the newborn should be closely followed up with sonography, as they may represent purely cystic neuroblastomas. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound , 43 :126–128, 2015