A Rare Case of Retroperitoneal Abscess Caused by Nephro-Colic Fistula Resulting from Staghorn Calculus

BACKGROUND Nephro-colic fistulas are uncommon, generally caused by local inflammation, trauma, or neoplasia affecting the kidney or the colon. Their association with a coralliform stone is described in a few case reports, but their management is difficult and differs quite a lot, depending on the clinical situation. We report an atypical clinical case of a reno-colic fistula associated with a staghorn calculus. This case adds to the literature an iconography rarely found. CASE REPORT A 68-year-old woman presented to the Emergency Department with respiratory symptoms and chronic abdominal pain. The biological results showed a high inflammatory syndrome. The radiological assessment revealed a retroperitoneal and left retro-renal abscess, attributed to a left nephro-colic fistula associated with the partial passage of a lithiasis within the colonic lumen. Colonoscopy confirmed the diagnosis. Multiple recurrences of diverticulitis in this region could be the origin of the complication. First, the patient was treated with antibiotic therapy and radiological drainage. Second, she benefited from a left nephrectomy, left segmental colectomy, and splenectomy. The clinical and radiological evolution were favorable after surgery. The follow-up was disrupted by hospitalizations in the Cardiology Department for cardiac decompensation. CONCLUSIONS Kidney stones along with local inflammatory phenomena can be the cause of a nephro-colic fistula. Due to the lack of guidelines in such cases, their diagnosis and management are difficult to ascertain. Surgery is the right course of treatment.