To review the pathophysiology of rhabdomyomas and the emerging option of prenatal treatment of fetal cardiac rhabdomyomas.We present a case of fetal rhabdomyomas causing significant hemodynamic compromise that received in-utero treatment of maternal sirolimus. Genetic amniocentesis confirmed a TSC2 mutation. A treatment program was initiated with a 10 milligram (mg) loading dose titrated to a goal maternal trough of 10-15 ng/dL. In order to follow fetal cardiac function, a sophisticated method of speckle tracking echocardiography was used before and after treatment. Obstetric ultrasound was used to monitor fetal growth, and clinical surveillance, echocardiography and brain MRI were used to monitor postnatal growth and development through six months of neonatal life.Sirolimus was initiated from 28 - 36 weeks of gestation with improvement of cardiac status. During this period, intrauterine growth restriction developed. Postnatally, the infant has had stable rhabdomyomas and cardiac function without reinitiating sirolimus. Brain MRI demonstrated scattered cortical tubers and subependymal nodules, and the infant has not had seizure-like activity. At six months of age the infant has achieved appropriate developmental milestones.In counseling cases of prenatal onset large obstructing rhabdomyomas and cardiac compromise, in-utero sirolimus treatment can be considered.
