A tumor weighing 800 grams was removed soon after birth in a baby girl born prematurely at 30 weeks gestation. The surgery was performed at the Bambino Gesù Children's Hospital in Rome. The baby is now in good health and about to be discharged. The removed mass, a sacro-coccygeal teratoma, is a rare neoplasm that develops at the end of the spine. While usually benign, it can lead to serious complications for the fetus. In the child's case, the mass underwent rapid growth that prompted specialists to perform a double surgery: at 28 weeks of gestation, at St. Peter Fatebenefratelli Hospital a team coordinated by specialists from Bambino Gesù Children's Hospital performed a minimally invasive intrauterine surgery that slowed the growth of the neoplasm by coagulating, by laser, the blood vessels that were supplying nutrients to the tumor. The baby was then followed to Bambino Gesù Children's Hospital, where the mother gave birth by scheduled C-section. After coming to light, the newborn - who weighed 1.9 kilograms before the surgery - was immediately operated on to completely remove the teratoma weighing about 800 grams. The operation, which lasted about 3 hours, also allowed reconstruction of the sacral region. Today, the little girl is in good clinical condition: she is breathing independently, feeding by mouth and is on her way home.