Chorionic Bump (CB) is a rare first-trimester sonographic feature described as an irregular, convex bulge from the choriodecidual surface into the first-trimester gestational sac (GS), with an incidence of 1.5-7 per 1000 cases. Etiopathology and related pregnancy outcomes are not clear. We present a case of a 37-year-old female with a transvaginal sonographic finding of a CB associated with a 47, XXY karyotype (Klinefelter syndrome) previously detected by non-invasive prenatal testing (NIPT) and confirmed by amniocentesis and definitive genetic examination at autopsy. To the best of our knowledge, this is the first case of CB associated to Klinefelter syndrome.