A diagnostic pitfall of postmortem CT in an abdominal stab wound: Peritoneal penetration without intraperitoneal gas or detectable intraperitoneal fluid.

Although intraperitoneal gas and fluid are important indirect findings suggesting peritoneal penetration on postmortem computed tomography (PMCT), these findings are not always present. We report a case of autopsy-confirmed peritoneal penetration without intraperitoneal gas or detectable intraperitoneal fluid on PMCT. A man in his 40s was found dead on a snowy slope with an abdominal stab wound. PMCT demonstrated discontinuity of the linea alba with interposition of adjacent fat tissue and a small mesenteric hematoma. However, neither intraperitoneal gas nor detectable intraperitoneal fluid was identified, and the wound was initially misinterpreted as superficial. Autopsy revealed a penetrating wound extending through the linea alba, greater omentum, transverse mesocolon, and small-bowel mesentery without injury to the bowel or solid organs. Intraperitoneal hemorrhage was minimal and not measurable, and hypothermia was determined to be the cause of death. This case demonstrates that the absence of intraperitoneal gas and detectable intraperitoneal fluid on PMCT does not exclude peritoneal penetration. Careful assessment of the wound tract and meticulous evaluation of subtle imaging findings suggestive of peritoneal penetration is essential for the accurate assessment of abdominal stab wounds.