A right atrium metastasis of breast cancer after long-term endocrine therapy

We report a case of right atrial metastasis in a 66-year-old female patient with breast cancer. The patient presented with palpitation and dyspnea after long-term endocrine therapy. A large echo-dense mass was found in the right atrium after the examination. In order to relieve the symptoms, the patient underwent a resection of the atrial lesion, and the pathology confirmed that it was metastatic breast cancer. Next-generation sequencing (NGS) of the entire exon was taken to explore the gene expression of the metastatic lesion. Forty-eighty genes were identified with mutations, and the mutations of ATM and ESR1 were considered to be associated with the development and metastasis of breast cancer in this case.