Abstract: Liver rupture is a serious, life-threatening event that is commonly due to blunt abdominal trauma, which should be suspected in a patient who is unconscious or unable to communicate. We report an autopsy case of a 28-year-old woman with severe developmental delay who presented to the emergency department with hemoperitoneum due to massive liver rupture and subsequently died without a diagnosis. An autopsy performed by the hospital pathology department confirmed hemoperitoneum due to hepatic rupture. The case was then referred to the medical examiner to exclude a traumatic etiology. After review of the clinical data, radiological images, and gross and microscopic pathological features, a diagnosis of peliosis hepatis was established. This rare entity has been reported previously as a cause of spontaneous, nontraumatic liver rupture and is reported here to demonstrate its characteristic features and potential to present as fatal hepatic rupture in circumstances in which occult injury must be excluded.