A Twin Inside a Twin/Fetus–in-Fetu–Review Article

Context: The case was described in a British medial journal in 1808 and is thought to occur in about one in every 500,000 births1. In recent years, similar births have occurred in India, Indonesia and in Singapore3. It is the process in which baby carries a twin inside them is called fetus in fetu.This is a rare condition characterized by abnormal embryogenesis in a diamniotic, monochorionic pregnancy4. Covering is made up of a fibrous membrane that contains some fluids (equivalent to the amniotic fluid) and a fetus attached by a cord or pedicle. In the uterus, the growth of an FIF initially similar to its twin, but stops suddenly because of either the vascular dominance of the host twin or any defect in the parasitic twin [2]. Parasitic twin mostly seen anencephalic, but in almost all cases its vertebral column and limbs are present (91% and 82.5%, respectively).