A 50-year-old male, with a medical history of Lynch syndrome and transurethral-resection (TUR) secondary to multifocal bladder tumour (pT1-high grade) with normal subsequent follow-ups, consulted for anal pain, rectal tenesmus and fever for 3 weeks. On examination, he presented perianal oedema and, on digital rectal examination, a right lateral orifice was palpable at 6cm from the anal margin. CT scan revealed a defect-in-continuity in the right rectal wall which communicated with bilateral perirectal collections extending towards the puborectalis-levator ani. On the right side, it extended towards the ischiorectal fossa and, on the left side it continued with another collection that displaced the corpus cavernosum. Urgent transanal debridement of abscess with biopsy and cultures was performed. Subsequent evolution was torpid. The clinical history was reviewed, as the patient had undergone repeated bladder catheterizations after TUR and BCG therapy one year before. Abdominal tomography with urethral contrast and cystourethrography were performed, which confirmed the presence of a fistula in the bulbomembranous urethra that communicated with the perirectal abscesses. Cultures and biopsies were negative for mycobacteria and malignancy was ruled out. A new surgical exploration was carried out, enlarging the transanal drainage orifice, making a temporary intestinal stoma and bladder catheterization. After eighteen weeks, the healing of the fistula was verified through of a new cystourethrography. Reconstruction of the intestinal transit has now been scheduled, after radiologically and endoscopically verifying the closure of the rectal orifice.