We report the case of a 15-year-old girl with a large gluteal and perineal rhabdomyosarcoma diagnosed at 24 weeks of pregnancy, whose management posed a great clinical dilemma for us. The patient refused to consider a therapeutic abortion, so we opted for a customized treatment with mild doses of chemotherapy administered weekly to control tumor growth while minimizing fetal and perinatal complications. After the delivery of a healthy female, we adopted a more intensive chemotherapy regimen plus irradiation. Despite an initially good response, the disease unfortunately progressed and the patient died of her disease.