A 9-year-old boy in India had a 7-millimeter stone lodged low in the ureter, the tube that carries urine from his left kidney to his bladder. Twelve days later, an X-ray showed the stone was no longer there. It had not been passed. It had moved back up, against the normal flow of urine, to the region of his kidney.
Urologists at MGM Medical College and Hospital in the Mumbai area reported the case in Urology Case Reports, published online Sept. 7, 2026. "To our knowledge, this is the first reported paediatric case of spontaneous retrograde migration of a ureteric calculus in world literature," they write. Earlier reports of stones moving backward involved only adults.
