A 26-year-old woman has felt a breast lump for the past month and is worried because she has a family history of early onset and bilateral breast cancers. On physical examination, there is a firm, 2-cm mass in the upper outer quadrant of her left breast. A biopsy is done, and the specimen microscopically shows carcinoma. Genetic analysis shows that she is a
carrier of the BRCA1 gene mutation, as are her mother and sister. Which of the following histologic types of breast carcinoma has the highest incidence in families such as hers?
Answer : D Medullary carcinoma
Patients with the BRCA1 gene mutation have a high incidence of medullary carcinomas that are poorly differentiated, do not express the HER2/neu protein, and are negative for estrogen and progesterone receptors.