Cardiac rhabdomyomas in tuberous sclerosis complex: clinical manifestations and genotype correlations

Background: Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder characterized by hamartoma formation in multiple organs, including the heart. Cardiac rhabdomyomas (CRs) are the most common cardiac tumors in infancy and occur in up to 80% of individuals with TSC. While CRs often regress spontaneously, their clinical impact varies, particularly concerning arrhythmias and obstructive complications. This study aimed to assess the incidence, clinical manifestations, and regression rates of CRs in infants and children with TSC, with a focus on genotype-phenotype correlations. Methods: We conducted a retrospective, single-center study of 22 patients with TSC and confirmed CRs, admitted to the pediatric unit of Policlinico “Gaspare Rodolico” in Catania between 2014 and 2023. Data were collected from medical records, including echocardiographic findings, electrocardiograms, and genetic analysis of TSC1 and TSC2 mutations. Statistical analysis was performed using chi-square and Student’s t-tests, with a significance threshold of p < 0.05. Results: Cardiac rhabdomyomas (CRs) were detected prenatally in 10/22 patients (45.5%) and at birth in 18/22 (81.8%). Multiple tumors were present in 17 patients (77.3%), with the anterolateral wall of the left ventricle being the most frequently involved site. Ten patients (45.5%) were asymptomatic, while 12 (54.5%) presented with arrhythmias or structural cardiac abnormalities. Antiarrhythmic therapy was required in three patients (13.6%), and surgical intervention in two (9.1%). Complete regression occurred in 3 patients (13.6%), while partial or marked reduction was observed in the majority. TSC2 mutations were associated with a higher rate (42.9%) and velocity (18.7% per year) of tumor regression compared to TSC1 mutations (25% and 12.4% per year, respectively). Conclusions: CRs are early manifestations of TSC that frequently regress, yet their potential for causing hemodynamic and electrical complications necessitates close monitoring. Patients with TSC2 mutations appeared to exhibit a trend toward faster tumor regression, although this observation requires confirmation in larger prospective studies.