Multifocal Kaposiform Hemangioendothelioma Causing Massive Fetal Chylous Ascites

Kaposiform hemangioendothelioma (KHE) is a locally aggressive vascular tumor that usually occurs in soft tissues of the extremity and rarely in the retroperitoneum. We report a unique case of isolated massive fetal ascites attributed to KHE, involving the retroperitoneum and multiple visceral organs, along with the Kasabach-Merritt phenomenon. We suspect that retroperitoneal KHE might have caused massive fetal ascites because of its high potential to invade the lymphatic vessels aggressively in the retroperitoneal space, which possibly permits intestinal lymph leakage into the peritoneal cavities.