Parapelvic cyst: A rare cause of ureteropelvic junction obstruction in a pediatric patient managed with robotic cyst decortication

Abstract

We report a case of a right parapelvic renal cyst causing intermittent ureteropelvic junction obstruction (UPJO). A 13-year-old male was referred for right flank pain. Stone protocol CT revealed renal pelvis dilation with punctate stones. Due to concern for intermittently obstructive calculi, he underwent ureteroscopy, which was unremarkable. A diuretic renogram showed symmetric uptake with partial emptying on the right with pain after diuretic administration. In office, we potentiated a Dietl's crisis with ultrasound obtained before and after fluid intake. Comparison of ultrasounds revealed a parapelvic cyst causing calyceal dilation. He was counseled for robotic cyst decortication and possible pyeloplasty. A robotic cyst decortication was performed. Once decorticated, the cyst base was fulgurated and pararenal fat was interposed into the cyst base. Console time was 70min with minimal blood loss. The patient was discharged post-operative day 1. Follow-up renal ultrasound at 4 months demonstrated resolution of hydronephrosis and parapelvic cyst. Parapelvic renal cysts causing intermittent UPJO is a rare entity that may be missed on a diuretic renogram. Clinical suspicion and appropriate imaging with ultrasound or magnetic resonance imaging are useful. Robotic cyst decortication is a technically feasible approach to treat this condition.