Metastasis of Breast Carcinoma to Intercostal Muscle Detected by Breast MRI: A Case Report

women and the second most important cause of death from cancer (1). The tumor size, lymph node status, and histological tumor grade of the tumor nuclei are important factors determining the likelihood that metastatic disease develops (2). The primary prognostic factor for breast cancer is axillary lymph node metastasis (3). The significant cause of death in patients with breast cancer is the neoplastic extension to vital organs (4). For that reason, from onset, breast cancer has been regarded as a systemic disease (4). The most frequent sites of metastasis from breast cancer, in decreasing order, include lung, bone, lymph nodes, liver, and pleura (4). On the other hand, metastases to skeletal muscle are extremely rare (5, 6). To our knowledge, there is no report of intercostal muscle metastasis from breast cancer in the literature. So, we present a case of metastatic involvement of the intercostal muscle from breast cancer with image findings.