Fetus in fetu: A rare case report

BACKGROUND: Fetus in fetu is a rare congenital anomaly in which malformed fetus grows within the body of its twin. It is almost always detected as an abdominal mass in infancy. It is a parasitic twin of a diamniotic, monozygotic twin. It should be differentiated from teratoma which has no axial arrangement and has got definite malignant potential. Herein, we present a case of a two-month old female infant and review the literature. Although fetus in fetu is a rare condition, correct diagnosis using imaging can be made before surgery. It should be considered as a differential diagnosis for lump abdomen especially in infants. Complete excision is curative.