Anteroposterior abdominal radiograph shows a soft-tissue mass in the right hemiabdomen. The mass contains calcified osseous-appearing structures of varying sizes and shapes. The postoperative specimen from the previous image shows a fairly well developed<unk>  lying on its back, with rudimentary digits. A computed tomography scan of the same patient's abdomen pre-operation reveals a large retroperitoneal soft-tissue mass. There are long hyperdense opacities that resemble fetal bones.<unk>  (or<unk>  in foetu) is a developmental abnormality in which a mass of tissue resembling a<unk>  forms inside the body of its twin. An early example of the phenomenon was described in 1808 by George William Young. There are two theories of origin concerning<unk> ". One theory is that the mass begins as a normal<unk>  but becomes enveloped inside its twin. The other theory is that the mass is a highly developed teratoma.<unk> " is estimated to occur in 1 in 500,000 live births.
Fetus in fetu
Maternal-fetal conflict
Abortion in Brunei
Fetal warfarin syndrome
Fetal hydantoin syndrome
Uremic fetor
Parasitic twin
Fetal trimethadione syndrome