Pelvic hematoma necessitans--a delayed complication of massive hemorrhagic pelvic fracture: case report.

Pelvic hematoma necessitans (PHN), a complication of massive hemorrhagic pelvic fracture, is reported in a 48-year-old pedestrian hit by an automobile. It was manifested by a tense hematoma of the buttocks and perineum that spontaneously "necessitated" or drained posterior to the anus 11 days after injury, resulting in complex anorectal morbidity and fecal contamination of a retroperitoneal hematoma and pelvic fracture sites. Early recognition, prompt diverting colostomy, and aggressive wound management are necessary after open pelvic fracture to prevent local and systemic infectious sequelae of PHN.