(i) Hamartoma composed of cardiomyocytes; (ii) the tumor is round or oval in different sizes; (iii) the boundary with the surrounding tissue is clear, gray-white, and has no capsule; (iv) there are “spider cells”; (v) PAS staining was positive, specific expression of striated muscle characteristic actin, desmin, myoglobin and other immunohistochemical markers, but not ki-67. This evidence concerns the gene MB and hamartoma.