Proteus syndrome, a disorder which consists of skeletal, hamartomatous and other mesodermal malformations proves to be tremendously variable. Although most of the patients show deformities at birth, the diagnosis is usually made later in life as the phenotype develops over time. We report on the case of a fetus presenting in utero, with a cystic abdominal mass and malposition of the fingers, which was found to have additional features of Proteus syndrome after termination of pregnancy. This case demonstrates that severe cases of Proteus syndrome can be detected prenatally.