Recurrence of large cardiac rhabdomyoma and pre-excitation syndrome in an infant after sirolimus therapy

Cardiac rhabdomyomas are the most common benign paediatric cardiac tumours. Arrhythmias and cardiac conduction abnormalities have both been described with these tumours and resolved with reduction in size of the tumours. Here, we present a case of a child who was prenatally diagnosed with multiple cardiac rhabdomyomas and cardiac arrhythmias and found to have ventricular pre-excitation after birth, in whom the tumours regressed, and pre-excitation resolved with 12 weeks of sirolimus and propranolol therapy. However, 8 weeks after cessation of sirolimus and propranolol therapy, tumour size increased, and manifest ventricular pre-excitation recurred and progressed to ventricular tachycardia. Subsequent follow-up after restarting sirolimus and propranolol therapy showed a significant reduction in tumour burden and resolution of pre-excitation. Conclusions: This finding underscores the need for risk stratification among patients with cardiac rhabdomyomas to identify those that need more prolonged medical treatment or closer monitoring.