Case Report: Multidisciplinary collaboration for the treatment of severe necrotizing fasciitis in the perineum caused by rectal cancer perforation.

Fournier's gangrene (FG) is a rare but life-threatening necrotizing fasciitis of the perineum and genital regions. Rectal cancer perforation is an uncommon cause of FG, and optimal management remains challenging. Case presentation: We report a 62-year-old male with rectal cancer complicated by severe FG secondary to rectal perforation. The patient underwent emergency fecal diversion, repeated extensive perineal debridement combined with vacuum-assisted closure (VAC) therapy, and intensive supportive care. Following infection control and clinical stabilization, definitive surgical management was performed, including laparoscopic abdominoperineal resection and reconstruction of the large perineal defect using a vascularized gracilis muscle flap and a gluteus maximus fascia composite flap. At two-month follow-up, the patient demonstrated complete wound healing, stable colostomy function, and recovery of independent daily activities. Conclusions: This case highlights the complexity of managing FG associated with rectal cancer perforation and demonstrates the feasibility of sequential treatment strategies integrating infection control, oncologic resection, and reconstructive surgery.