SỎI NIỆU QUẢN GIẢ HÌNH HẸP KHÚC NỐI BỂ THẬN - NIỆU QUẢN Ở TRẺ EM: BÁO CÁO CA LÂM SÀNG

Abstract

Background: Ureteropelvic junction (UPJ) obstruction is the leading cause of hydronephrosis in children. Radiolucent or matrix ureteral stones are rare but may cause secondary UPJ obstruction via chronic inflammatory remodeling, mimicking primary congenital anomalies and constituting a dangerous diagnostic trap.

Case Presentation: A 5-year-old boy was incidentally found to have Grade I left hydronephrosis in 2022 and managed conservatively. In November 2023 he presented with acute recurrent vomiting, feeding intolerance, and CRP 13.5 mg/L. Ultrasonography showed Grade II hydronephrosis with proximal ureteral dilatation (8.3 mm). Contrast-enhanced CT revealed a 6×7 mm soft-tissue filling defect at the proximal ureter with an abrupt cut-off sign, suspicious for a radiolucent calculus. On December 26, 2023, transperitoneal laparoscopic pyelolithotomy combined with Anderson-Hynes dismembered pyeloplasty was performed. Intraoperatively, a sludge-like matrix stone was retrieved along with a severely tortuous, inflamed, and fibrotic proximal ureter confirming secondary UPJ stenosis. At 18-month follow-up (June 2025), the renal pelvis measured 15 mm APD with the patient remaining entirely asymptomatic.

Conclusion: Radiolucent stones can induce irreversible fibrotic secondary UPJ obstruction in children. Stone extraction alone may be insufficient when fibrotic stenosis is established; concurrent formal pyeloplasty should be strongly considered. Persistent postoperative dilatation likely represents chronic structural remodeling rather than surgical failure and should not prompt unnecessary re-intervention.