Sudden Unexpected Perinatal Death Due to Undiagnosed Diffuse Placental Chorioangiomatosis.

Chorioangiomatosis is a rare placental vascular disorder that may lead to severe fetal compromise and, in exceptional cases, sudden perinatal death. Its prenatal diagnosis remains challenging because diffuse lesions may lack a discrete placental mass and escape routine ultrasonographic detection. We report a case of sudden unexpected neonatal death occurring immediately after delivery following an apparently uncomplicated full-term pregnancy. External and macroscopic internal postmortem examinations were unremarkable. Histological evaluation revealed signs of chronic intrauterine hypoxia, while placental examination demonstrated diffuse chorioangiomatosis characterized by widespread capillary proliferation within immature chorionic villi and vascular wall hypertrophy. These findings supported a diagnosis of placental insufficiency leading to fatal hypoxia. This case highlights the critical role of placental histopathology in the forensic investigation of perinatal deaths, particularly when routine autopsy findings are negative. It also underscores the limitations of prenatal imaging in detecting diffuse placental vascular lesions. Recognition of this entity is essential to avoid misclassification of death and to ensure appropriate medico-legal assessment.