Unusual cause of Fournier's gangrene: colorectal-genitourinary tract fistulae status post brachytherapy.

There are few reports of radiation associated colorectal-genitourinary tract (CRGU) fistulae causing Fournier's gangrene (FG). We describe a case of FG in a patient with possibly two CRGU fistulae in the context of previous high-dose brachytherapy and external beam radiation therapy for prostate cancer. Unfortunately, CRGU fistulae are not well classified as significant risk factors for the development of FG. Our case demonstrates the rationale for maintaining a broad differential in patients presenting with recurrent urinary tract symptoms or necrotising soft tissue infections to include undiagnosed fistulae.