September 21st 2020
Breast metastasis from extramammary malignancy is rare, with a reported incidence rate of 0.4% to 1.3% in the published literature. The primary malignancies that most commonly metastasize to the breast are leukemia, lymphoma, and malignant melanoma. Here, we report a very rare case of metastatic EGFR-mutated non–small cell lung cancer (NSCLC) in the breast detected by screening mammography. The patient had initially been diagnosed with a clinical stage IIIA NSCLC and had been treated with neoadjuvant chemoradiation followed by curative-intent surgery. Several interesting aspects of the case, along with a discussion of evolving adjuvant and frontline metastatic management options in EGFR-mutated NSCLC, will be presented.