"A dicey situation:" asymptomatic hypertensive urgency caused by DICER1 mutation-derived cystic nephroma in a 12-month-old.

Cystic nephroma (CN) in pediatric patients is a rare, benign, multi-lobular cystic mass often indicative of DICER1 tumor predisposition syndrome. This condition is caused by a germline mutation of the DICER1 gene and requires appropriate follow-up to monitor for other DICER1-associated tumors in the lungs, thyroid, ovaries, and kidneys. We describe a 12-month-old female who presented with hypertensive urgency in the setting of a new large abdominal mass ultimately diagnosed as a cystic nephroma. We discuss the successful management of the patient's hypertensive urgency with oral medication and resolution of her hypertension after a left nephrectomy. We also review differential diagnoses for large pediatric renal masses, appropriate treatments, work-up for patients with CN, and the necessary screening schedule for individuals with confirmed DICER1 tumor predisposition syndrome.