<p>Medullary breast cancer is a rare subtype of invasive breast cancer, representing from 0.2% to 6% of all breast carcinomas, with a higher proportion among women with triple-negative breast cancer and among those with a <i>BRCA1</i> mutation. This review article aims to investigate the frequency of medullary breast cancer among all breast cancers and to assess its association with <i>BRCA1</i> mutations. We surveyed studies involving patients diagnosed with breast cancer that report both the histology of the breast cancer as well as the presence of <i>BRCA1</i> mutations. Among women with medullary breast cancer, the proportion of cases that carry a <i>BRCA1</i> mutation ranges from 3% up to 35.3%, depending on the study. Among <i>BRCA1</i>-mutated breast cancers, the proportion that are medullary ranges from 8 to 20%. Given the notable association between medullary breast cancer and <i>BRCA1</i> mutations, we propose to consider medullary breast cancer as a criterion for genetic testing in order to improve the identification of a larger number of carriers, thereby enhancing screening and prevention strategies.</p>