Divergent outcomes of delayed ureteropelvic junction stenosis after renal cyst sclerotherapy: two case reports.

Rare long-term complications, such as ureteropelvic junction (UPJ) stenosis, can occur after renal cyst puncture and sclerotherapy and lead to severe hydronephrosis with renal impairment. We illustrate these risks with two examples: in one case, a delayed diagnosis led to severe perirenal fibrosis and renal failure at operation; in the other case, early laparoscopic pyeloplasty preserved renal function. The marked differences illustrate that this complication often has a mysterious onset and long latency, highlighting the importance of early detection and treatment. Clinicians should maintain a high index of suspicion, inform patients of long-term risks before the procedure, and implement long-term follow-up. Regular imaging monitoring can allow early diagnosis and treatment, which reduces the risk of irreversible renal function loss.