Introduction: Calyceal diverticula (CD) are cystic structures arising from the renal parenchyma lined by urothelial epithelium. A narrow infundibulum connects the diverticulum to the collecting system. In contrast to a simple renal cyst, they are non-secretory and the cavity fills passively with urine. Patients may be clinically asymptomatic, or present with flank pain, gross hematuria, urinary tract infection or renal stones. CD mimic simple renal cysts on ultrasound (US), therefore dedicated imaging of the collecting system is necessary to confirm the diagnosis. Treatment options include endoscopic, open, and minimally invasive modalities. In this video, we present our technique for evaluation and management of a massive type II calyceal diverticulum in a pediatric patient.
Methods: We present a case of a pediatric patient with a massive lower pole calyceal diverticulum diagnosed by magnetic resonance urogram, treated with robot assisted laparoscopic calyceal diverticulectomy.
Results: Our patient is a 17-year-old female with a 10 cm right lower pole cyst discovered incidentally on evaluation of proteinuria. Renal US demonstrated a 10 cm right lower pole renal cyst with right upper pole SFU grade II hydronephrosis, likely due to mass effect. MR urogram was performed, which demonstrated a CD with communication with the renal pelvis, and non-obstructive right upper pole hydronephrosis. Cystoscopy with retrograde pyelogram demonstrated dilute contrast entering a lower pole calyceal diverticulum, without ostium identified. A robot assisted laparoscopic diverticulectomy was performed. Retrograde injection of methylene blue via ureteral catheter facilitated identification of the infundibulum, which was closed in 2 layers. Total operative time was 240 minutes and blood loss was minimal. The patient was discharged postoperative day one. She is doing well and renal ultrasound at 2 months postoperative demonstrates resolution of the hydronephrosis and CD.
Conclusions: We must maintain a high index of suspicion for CD, as they mimic other renal pathology on US. Dedicated collecting system imaging such as MR urogram is needed to confirm the diagnosis. The use of intraoperative retrograde injection of methylene blue can identify infundibula not seen on gross inspection. Robotic diverticulectomy demonstrates high success and low complication rates in appropriately selected pediatric patients.
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