Delayed presentation of retained renal shrapnel: a case report and literature review.

Retained renal foreign bodies (FBs) following blast or firearm injury are rare and usually present early; delayed presentation is a challenging diagnostic scenario. The present report describes a case of retained renal shrapnel presenting with obstructive complications 18 years after the initial injury. Imaging revealed a 24 mm calculus encrusting a retained metallic FB at the left renal hilum, with severe hydronephrosis and reduced differential renal function (27.4%). Following ureteroscopic stenting, percutaneous nephrolithotomy was performed. The surrounding calculus was fragmented, but the metallic core resisted both pneumatic and laser lithotripsy and required extraction via a dorsal lumbotomy. A focused review of seven prior cases revealed an injury-to-presentation latency of 5 months to 17 years; the present 18-year interval is among the longest reported. Retained renal FBs may remain silent for years and closely mimic ordinary calculi; a thorough trauma history is essential to avoid misdiagnosis and guide operative planning.