Renal Cyst Rupture Mimicking Grade V Renal Trauma After Blunt Injury: A Case Report Highlighting the Risk of Radiologic Overstaging.

Blunt renal trauma is commonly assessed using contrast-enhanced computed tomography (CT), which guides management decisions based on injury grading. However, pre-existing renal pathology may confound imaging interpretation and lead to an overestimation of injury severity. We report the case of a previously healthy 26-year-old male patient presenting with flank pain and hematuria after blunt abdominal trauma during a soccer (football) match. Contrast-enhanced CT demonstrated findings suggestive of American Association for the Surgery of Trauma (AAST) grade V renal injury, including apparent parenchymal lacerations, a large perirenal hematoma, and active contrast extravasation. Bilateral renal cysts and hepatic cysts were also identified, raising suspicion for underlying cystic kidney disease. Despite alarming imaging findings, the patient remained hemodynamically stable and was successfully managed conservatively, with no clinical or radiological progression. This case highlights renal cyst rupture as an important differential diagnosis in patients with cystic kidney disease presenting with apparent high-grade renal trauma and emphasizes the importance of integrating imaging findings with clinical stability to avoid unnecessary invasive interventions.