An unusual tumour: Hamartoma of mature cardiac myocytes.

Heart neoplasms are uncommon and usually benign. Hamartoma of mature cardiac myocytes is an unusual lesion with only a few reported cases. It is a heterogeneous mixture of well-differentiated myocytes, fibroblasts, adipocytes and blood vessels. We present a case of hamartoma of mature cardiac myocytes and a concise review of the pertinent literature. A multi-lobulated polypoid tumour attached to the wall of the right atrium was found during an autopsy of a young woman. Microscopy revealed cardiomyocytes, fibrous connective tissue and well-differentiated adipocytes. The immunohistochemical study had a positive immunoreactivity for desmin, muscle-specific actin (HHF-35) and CD34 markers, showing the different types of mesenchymal cells involved. This combination of markers has not been previously used. Other tumours, such as cardiac rhabdomyoma and cardiac myxoma were ruled out due to the differences in histological characteristics and clinical presentation.