Retroperitoneal Fibrosis and Hydronephrosis due to Actinomycosis

Purpose: In this article, we present a case of actinomycosis causing fibrosis and bilateral obstructive uropathy. Methods: A 43-year-old woman was admitted to the hospital with left flank pain. Abdominal computed tomography showed bilateral hydroureteronephrosis and a malignant mass. The fine-needle aspiration biopsy was reported as retroperitoneal fibrosis. Stents were placed in both ureters. Two (2) months later, laparotomy revealed a mass located just below the origin of the inferior mesenteric artery. Bilateral ureterolysis and sigmoid colon resection was performed. Results: The pathology report was fibrosis and actinomycosis. She was given parenteral crystallized penicillin 4 x 5 million units/day for 21 days, followed by oral cotrimoxazole (960 mg) for 6 months. Conclusions: Because actinomycosis was not diagnosed either radiologically or pathologically, the patient underwent immunosuppressive therapy for 2 months preoperatively.