A 24-year-old woman notes a lump in her right breast for the past month. She is concerned because her sister was diagnosed with poorly differentiated "triple-negative" breast cancer at age 31. Ultrasonography of the breast shows a solid mass. Fine needle aspiration is attempted but no diagnostic cells are obtained. Mammography is performed and there is a single 1-cm density with small clustered calcifications in the right breast but no lesions of the opposite breast. Which of the following is the best course of action for this patient?

Her age would suggest the lesion is probably benign, and even fibroadenomas and fibrocystic changes can have calcifications. The fibrous component of fibroadenoma or fibrocystic changes can make it difficult to aspirate cells from them. However, the family history and the mammographic appearance of small clustered calcifications are concerning for carcinoma. A delay in diagnosis and treatment of breast cancer decreases survival. Although BRCA1 mutations are associated with HER2 and ER- and PR-negative breast cancers, the lesion must still be diagnosed. Based upon the histologic findings and molecular markers, a treatment plan can then be instituted that may include additional studies and pharmacologic therapies.