Fetus-in-fetu: mimicking teratoma on antenatal ultrasound

Abstract Objectives Fetus-in-fetu is a rare congenital anomaly that occur secondary to abnormal embryogenesis in diamniotic monochorionic pregnancy. Its diagnosis can be accurately made by imaging ultrasonography, radiography, computed tomography, or magnetic resonance imaging. Differential an important issue because FIF, teratoma and cystic meconium peritonitis are very different terms of their respective disease courses. Case presentation This interesting case 22-year-old pregnancy woman, presented for routine antenatal ultrasound. The fetus-in-fetu was suspected, complete surgical excision the lesion performed histopathologically confirmed Conclusions We describe also common characteristic FIF as revealed prenatal postnatal US, MRI, operative findings.