Urologic Presentation of Unicentric Pediatric Castleman Disease in the setting of Acute Renal Colic.

11-year-old otherwise healthy female presented with renal colic and during computed tomography (CT) imaging evaluation, she was found to have a right distal ureteral stone with associated hydroureteronephrosis, medially deviated ureter, and 4 cm solid retroperitoneal mass. The mass was palpable on physical exam and was further categorized with magnetic resonance imaging (MRI), ultrasound, and laboratory testing. A multidisciplinary team approach including pediatric surgery, radiology, oncology, and urology led to the patient undergoing a right retrograde pyelogram, ureteroscopy with stent placement, and laparoscopic excision of retroperitoneal mass. Her pathology revealed lymphoid hyperplasia with histologic features of Castleman disease (CD).