Hamartomas of mature cardiac myocytes.

We present two paediatric cases of a very rare, pathologically benign, and primary cardiac tumour composed of mature cardiac myocytes with disorganized cytoarchitecture called hamartoma of mature cardiac myocyte. The patients are usually asymptomatic, may have non-specific electrocardiogram findings, and rarely have associated sudden death. The clinical presentation and pathological and imaging findings of this rare tumour are discussed. Cardiac magnetic resonance imaging may help differentiate this tumour from other common differential diagnosis like cardiac fibroma and hypertrophic cardiomyopathy.