Growth of Cardiac Fibromas During Infancy.

BACKGROUND: Cardiac fibromas commonly present in childhood as large intramyocardial tumors that are frequently associated with arrhythmias, hemodynamic compromise, sudden cardiac death, and/or associated cardiac or lung compression. Although unoperated cardiac fibromas were historically thought to remain stable in size throughout life, their natural history has not been studied. METHODS: In this retrospective single-center study, we identified all patients with cardiac fibromas and serial cardiovascular magnetic resonance (CMR) and/or cardiac computed tomography (CT) before or after surgical intervention to characterize fibroma growth. RESULTS: A total of 36 infants and children with at least 2 serial imaging studies were identified. Younger age at first imaging study was associated with faster cardiac fibroma growth, with infants (<12 months) demonstrating a body surface area (BSA)-indexed growth rate of 11 ± 2mL/m2/month; whereas children older than 2.5 years demonstrated no growth (p=0.005). In one child, the tumor's unadjusted volume increased by 933% and the BSA-adjusted volume increased by 334% between CMR examinations obtained in the first week of life and at age 1.5 years. A higher T2 tumor:myocardium intensity ratio was associated with both younger age at initial examination and faster growth rate (p=0.001). A higher tumor growth rate was associated with the development of hemodynamic impact of the tumor, in particular pulmonary vein compression and/or lung compression. No significant tumor growth was observed after tumor resection. CONCLUSIONS: Cardiac fibromas may exhibit rapid growth in infancy, and tumor growth is associated with the development of hemodynamic compromise. Based on this observation, consideration should be given to frequent monitoring of tumor size and clinical status during the first years of life.