Fetus in fetu: rare Indian case of infancy

Fetus in fetu (FIF) is an extremely rare condition in which malformed twin develop inside the body of living twin. It is most commonly found within the retroperitoneum. Currently, at least 200 cases have been reported across the globe, yet very few instances seen in India. We describe a case of five months old infant born via normal vaginal delivery. She had a firm palpable mass measuring 7×10×7 cm in the left hypochondriac epigastric region crossing midline. A preoperative diagnosis of FIF was made by using ultrasonography (USG) and computed tomography (CT). An exploratory laparotomy and excision of mass was performed successfully. The excised mass was proven to be FIF on the basis of gross and histopathological examination. Even though teratoma is a differential diagnosis, surgical removal is the most suitable treatment method.