The heart is an organ where primary malignant
tumors rarely develop. In particular, the incidence of cardiac
rhabdomyosarcoma (RMS) is extremely low. It has been reported that the risk of second malignant
tumors in mediastinum is increased by
radiotherapy in women with
breast cancer. However, little is known about the association between irradiation to heart and cardiac RMS. Here, we report a case of a 68-year-old woman with primary cardiac RMS. She suddenly presented
syncope at a workplace, and was taken to the emergency room at our hospital. Several imaging tests, including echocardiogram and cine magnetic resonance imaging, detected two
tumors in the right ventricle (RV) and its outflow tract, which had almost obstructed the main trunk of the pulmonary artery (PA). To avoid sudden PA occlusion by the
tumor, we emergently performed surgical excision of the
tumors from the RV. Pathological analysis revealed that these
tumors were embryonal type RMS. She had received
radiotherapy after
mastectomy for left
breast cancer 18 years previously, and no recurrence of
breast cancer had been detected. This cardiac RMS is considered as a second malignant
tumor related to
radiotherapy for
breast cancer. <Learning objective: We experienced a 68-year-old woman having two
tumors of the RMS in RV, who had received
radiotherapy for left
breast cancer 18 years previously and had previously presented no recurrence. There is literature suggesting that
radiotherapy may increase the risk of
soft-tissue sarcoma in women with
breast cancer. We should be aware of cardiac RMS as a second malignant
tumor related to
radiotherapy for
breast cancer, although its incidence is extremely low.>.