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. 2019 Annals of Translational Medicine. All rights reserved.