Fetus in fetu: A rare case of intra-abdominal mass

Fetus in fetu is uncommon cause of retroperitoneal mass in infancy that resulted from abnormal embryogenesis. Clinical manifestations vary and mostly presented at infancy It is differentiated from teratoma through its location, benign course, and identification of limb buds and well-organized organs. Radiologically, identification of long bones and organized vertebral bodies are core in the diagnosis. Presented is 4 days-old male with abdominal distention as the main manifestation. Definite radiological diagnosis was done by Ultrasound (US) and computed tomography scan.