Fetus in Fetu – a rare entity

Abstract

Fetus-in-fetu is a rare condition, secondary to abnormal embryogenesis in a twin pregnancy. The malformed parasitic fetus is found in the body of its twin. It presents as a fetiform mass, usually in the abdomen of a newborn or an infant. The incidence is 1 per 500,000 births. It is a pathologic entity distinct from teratoma. Current imaging techniques may allow a correct pre-operative or a prenatal diagnosis of the condition. We present a case of a 2 month old male baby with abdominal distension noticed in the first week of life. The 'mass' was removed, the gross and microscopic features confirmed the diagnosis of Fetus-In-Fetu . key words: abdominal mass, fetus, fetus in fetu, parasitic twin, twin pregnancy.