EP1084 - Bleeding Through the Wrong Channel: Rectourethral Fistula Mimicking GI Hemorrhage

Purpose/Background: Rectourethral fistulas (RUFs) are a rare complication of prostate cancer, occurring in approximately 0.1-0.5% of cases, most often as a result of treatment-such as surgery or radiation-rather than direct tumor invasion. Spontaneous RUFs from locally advanced prostate cancer are exceedingly uncommon and carry a poor prognosis. In these cases, the RUF represents direct invasion of the rectum by prostate cancer, indicating locally advanced T4 disease. An 87-year-old male presented to the emergency department with gastrointestinal bleeding initially presumed to be caused by a rectourethral fistula related to chronic Foley catheter use, placed after a failed TURP for urinary retention. However, further investigation revealed the fistula was secondary to an invasive prostate cancer.

Methods/Interventions: An 87-year-old male with a complex medical history presented to the emergency department with a three-week history of worsening rectal bleeding, with large volumes of bright red blood, accompanied by dizziness. His medical history included type 2 diabetes mellitus, chronic kidney disease, hypertension, gastroesophageal reflux disease (GERD), thalassemia, and Lynch syndrome due to a pathogenic MSH2 mutation. He also had a history of colon cancer (status post right hemicolectomy in 1994) and a right ureteral neoplasm treated with ureterectomy without radiation. Six months prior to arrival, the patient had experienced persistent urinary retention and underwent transurethral resection of the prostate (TURP) , with benign pathology. A chronic indwelling Foley catheter had been maintained since the procedure. On presentation, a CTA of the abdomen and pelvis showed active arterial extravasation into the rectal lumen, raising suspicion for a fistulous connection between the prostate and the anterior rectal wall. Interventional radiology preformed successful prophylactic embolization of the bilateral distal superior rectal arteries. A suprapubic catheter was placed for urinary diversion to aid in fistula healing. However, transanal examination by colorectal surgery identified a friable, invasive mass originating from the prostate and eroding into the rectum, involving roughly half the rectal circumference. A transrectal biopsy of the mass revealed a poorly differentiated adenocarcinoma of prostatic origin.

Results/Outcomes: RUFs are often managed with diversion, as spontaneous closure is rare. However, in malignant RUFs, identifying the underlying cancer is critical. In this case, transanal biopsy was essential in guiding management including androgen deprivation therapy and radiotherapy targeting the prostate and pelvis.

Conclusion/Discussion: Lynch syndrome, particularly in individuals with MSH2 mutations, is associated with an increased risk of prostate cancer, MSH2 carriers have a 2-5 times greater risk, with a lifetime prostate cancer risk of up to 30%. This genetic context supports the need for careful malignancy surveillance in older Lynch syndrome patients presenting with atypical genitourinary symptoms. The most common presenting symptoms of rectourethral fistulas include hematuria, pneumaturia, and fecaluria. Significant rectal bleeding is rare but may occur in cases involving malignancy or prior radiation, due to tissue friability, necrosis, or vascular invasion. This patient's rectal bleeding initially suggested a benign RUF etiology related to chronic Foley use and prior TURP; however, further workup revealed a malignant RUF secondary to advanced prostate cancer.

Rectourethral Fistula
Intraoperative Transanal Examination of Invasive Prostate Carcinoma