DOI: https://doi.org/10.36347/sjmcr.2026.v14i05.010

Pages: 906-910

Background: Emphysematous pyelonephritis (EPN) is a rare, life-threatening necrotizing infection of the renal parenchyma characterized by gas production, predominantly affecting patients with uncontrolled diabetes. Concurrently, Bosniak IV renal cysts are complex cystic masses with solid enhancing components that carry a high suspicion of malignancy (cystic renal cell carcinoma). The simultaneous occurrence of these two distinct pathologies in the same kidney is an extremely rare clinical entity. Case Presentation: We present the case of a 68-year-old diabetic male admitted for febrile lumbar pain and subocclusive syndrome. Computed tomography (CT) revealed right-sided EPN (gas, hydroaeric levels, pneumocalices) coexisting with a Bosniak IV cyst in the upper pole. This association created an initial therapeutic dilemma: standard percutaneous drainage of the collection was contraindicated due to the risk of tumor seeding along the needle tract. A sequential approach was adopted, initiating with broad-spectrum intravenous antibiotics (Piperacillin-Tazobactam) and internal urinary diversion via a JJ stent. Although renal function improved (creatinine decreasing from 47.9 mg/L to 19 mg/L), follow-up ultrasound revealed persistent perirenal collections infiltrating the psoas. Consequently, a targeted percutaneous nephrostomy was performed, carefully avoiding the cystic lesion. Conclusion: This exceptional association creates a "therapeutic collision" between an infectious emergency requiring drainage and oncological caution requiring surgical integrity. A sequential, individualized approach guided by dynamic imaging and multidisciplinary discussion proved successful in controlling the infection while preserving oncological options.