Impact of prenatal diagnosis of fetus-in-fetu

E.K. Sewell*, B. Massa-Buck, E.I. Rubio, A.N. Massaro, A. Badillo, E. Puscasiu, R. Broth, T. Falika-King, B. Nies, A. Penn | JNPM 2017;

Fetus in fetu (FIF) is an extremely rare condition (1/500,000 live births) in which a fetiform structure is incorporated into the body of its twin. FIF can be a diagnostic dilemma due to its similarity to a teratoma, but identification of FIF is important for subsequent medical and surgical management. We compare two cases of fetal masses diagnosed on prenatal imaging that were later identified as FIF through further radiological, surgical, and pathologic evaluation. We use these cases to illustrate key pre- and postnatal features of FIF and highlight the benefits of prenatal detection and follow-up for postnatal management.

*Corresponding Author: 

Elizabeth Sewell, MD, MPH Emory University School of Medicine, 2015 Uppergate Drive, Room 318, 3rd Floor, Atlanta, GA 30322, USA. Tel.: +1 404 727 5141; Fax: +1 404 727 3236; E-mail: