Paediatric Cardiac Tumours: A National Population Study.

Paediatric cardiac tumours are rare. The most common tumour is a rhabdomyoma, a benign tumour of the myocardium associated with Tuberous Sclerosis Complex (TSC), a rare genetic condition caused by constitutional pathogenic variants in either the TSC1 or TSC2 genes. Although benign, complications related to obstructed flow through the heart or intractable arrhythmias occur. A 23-year retrospective study of patients referred to the National Scottish Paediatric Cardiology service with evidence of a cardiac tumour. 51 patients identified; 12 prenatally, 8 live born. Of the 47 patients born alive, 44 (93.6%) patients had a benign cardiac tumour and 3 (6.4%) a malignant tumour. Rhabdomyomas were shown to be the most common tumour type in patients with TSC (p = 0.000861) and overall. 8/44 (18%) benign tumours had a documented arrhythmia, 50% requiring treatment with beta blockade. 7 patients with rhabdomyomas received an mTOR inhibitor, 6 were recorded as TSC 2 genotype. There was significant extra cardiac symptom burden for the TSC subtypes (p = 0.00105), particularly TSC2, related to renal and neurological complications. The natural history of rhabdomyomas is slow regression and if no significant mass or rhythm disturbances in early childhood, a positive cardiovascular prognosis. Identifying cases associated with TSC is important to counsel families regarding the longer-term implications related to morbidity and mortality particularly in TSC2 associated cases, which typically have a more severe phenotype. Targeted medical therapy is indicated and shown to be effective for the treatment of benign cardiac tumours causing significant rhythm or mass effect. mTOR inhibitors should be considered in the treatment of rhabdomyomas and beta blockade for haemangiomas.