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.