Sigmoid (S-shaped) crossed-fused renal ectopia is a rare congenital anomaly, infrequently complicated by pediatric urolithiasis. We report a 3-year-old presenting with abdominal pain, diarrhea, and intermittent fever, previously diagnosed with a renal stone. Imaging revealed a 13-mm pelvic stone in the lower ectopic kidney with moderate hydronephrosis; laboratory tests were normal. The patient underwent open nephrolithotomy via a right modified Gibson incision, achieving complete stone removal through a small avascular parenchymal incision. Recovery was uneventful, and stone analysis showed mixed calcium oxalate and phosphate. Careful imaging and individualized surgical planning are essential in complex renal anatomy. • Sigmoid crossed-fused renal ectopia is a rare anomaly, occasionally presenting with urolithiasis in children. • Preoperative imaging is essential to localize stones and plan safe surgical access. • Endourological approaches are preferred, but open nephrolithotomy via modified Gibson incision allows safe stone removal in anatomically complex kidneys. • Postoperative recovery can be excellent with preservation of renal parenchyma in pediatric patients. • In developing countries, stone analysis and nutritional surveillance help prevent recurrence.
Hakimi et al. (Fri,) studied this question.