Retroperitoneal Extension of a Fistula-in-Ano: A Case Report.

Fistula-in-ano and anorectal abscesses are commonly encountered in surgical departments, but their extension into the retroperitoneum and pelvis to form an extensive collection is rare. Here, we present the case of a 66-year-old diabetic male who presented with lower abdominal pain and fever for a day, with signs of sepsis. He had a simple fistula in the perianal region for the past 15 years. Radiological studies showed that the fistulous tract was complex which extended superiorly into the supralevator space and the retroperitoneum and formed a localized collection in the pelvis. The dependent part of the collection was drained using minimally invasive techniques, and the remnant collection was surgically drained through a perianal approach. The patient's condition improved with further treatment and local wound care, and he was subsequently discharged.