Intrahepatic fetus-in-fetu: a case report and review of the literature.

The authors report the third case since 1964 of fetus-in-fetu presenting at Red Cross Children's Hospital. A fetal liver abnormality was detected during routine antenatal ultrasound scan, and the postnatal diagnosis of an intrahepatic, multiple fetus-in-fetu was made with abdominal ultrasound scan, plain radiograph of the abdomen and computed tomography. The mass was removed surgically by hemihepatectomy when the patient was 4 months of age. Imaging and the macroscopic and microscopic appearances of the abnormality confirmed the diagnosis and amplified it to include an adjacent teratoma. Multiple small subcapsular and perimass vascular hamartomas were coincidentally discovered in the liver. Two of the 3 nodules within the amniotic-lined cavity of the intrahepatic mass individually comply with the accepted criteria for fetus-in-fetu, and the third nodule has the accepted features of a benign teratoma. The existence of multiple fetus-in-fetu and fetus-in-fetu combined with a teratoma, is recorded in the medical literature. The imaging as well as the macroscopic and microscopic features are illustrated.