European Journal of Cardiovascular Medicine

Background: Foetus in foetus is a rare benign congenital anomaly. It occurs in 1 in 5,00,000 live births and almost < 200 cases are recorded so far1.. In FIF a malformed vertebrate foetus gets incorporated in living twin and presents as an abdominal mass with pressure effects. It is seen in Monozygoticmonochorionic diamniotic twins due to defect in embryo-pathogenesis causing asymmetrical division of blastocyst and malformed one draws blood and grows within live foetus. This benign condition mostly presenting in infancy or early childhood has to be differentiated from Teratoma with malignant transformation. Case presentation: A case of 10 days old female baby was brought by her mother with complaints of abdominal distension and excessive crying. The Ultrasound and CT scan of abdomen revealed, Extra gonadal teratoma.Serum levels of Alfa fetoprotein, Beta HCG(Human Chorionic Gonadotrophin) and CEA (Carcinoembryonic antigen) levels were found to be within normal limits. After surgical removal, specimen was sent for histopathological examination. Grossly mass was covered with glistening sac.On cut section,well-formed limb buds with fingers were noted along with different structures of variable consistency leading towards suspicion of Foetus in foetu. Microscopic appearance showed mature elements of epithelial and mesenchymal origin. Conclusion: Foetus in foetu is a rare anomaly and requires histopathological evaluation for well- aimed follow up as it has increased potential of malignant transformation.