CHAPTER 132 Breast Biopsy

An excisional breast biopsy is a technically straightforward outpatient procedure readily performed under local anesthesia. With appropriate training and experience, primary care physicians can become qualified to perform most simple breast biopsies. The challenge is to correctly identify which lesions are amenable to biopsy and which require referral to a breast (general) surgeon. The goals in the management of a patient with a breast mass should be to obtain the diagnosis in the most expedient manner, to achieve good cosmesis, and to preserve all therapeutic options if the mass is unexpectedly found to be malignant at biopsy.

The only definitive method for ensuring that a mass is benign is to remove tissue for pathologic examination. The missed or delayed diagnosis of a breast mass that ultimately proved to be cancerous is currently the most litigious aspect of medical practice. Failure to be impressed with physical examination findings was cited as the most common reason for the delay in the diagnosis of breast cancer. Benign masses are usually smooth, well circumscribed (round), and freely mobile; however, many cancers (e.g., colloid, medullary, and expansive intraductal) may mimic this presentation. Similarly, even though the incidence of breast cancer rises dramatically after age 65 years, 63% to 80% of lawsuits resulted from the missed diagnosis of cancer in women younger than 50 years of age. In addition, whereas the presence of a significant positive family history increases the suspicion that a palpable abnormality may prove to be malignant, two thirds of all women with the diagnosis of breast cancer have no identifiable risk factor. Nevertheless, it is important to remind our patients and ourselves that not all breast masses are cancerous.

The role of mammography in women with a breast mass is twofold. First, it can offer clues as to the degree of suspicion that the mass may be malignant. Worrisome mammographic features include the findings of a spiculated lesion, a mass associated with pleomorphic microcalcifications, or dermal edema and retraction. Second, it allows assessment of the remainder of the breast parenchyma in both the involved and contralateral breasts. Before proceeding with excisional biopsy, a baseline mammogram must be obtained to rule out the presence of an occult synchronous lesion that may alter the surgical approach. Moreover, if the mass is highly suspect, referral to a surgeon may be indicated to facilitate management of a presumed breast cancer. It is crucial to realize that failure of mammography or ultrasonography to visualize a discrete, palpable abnormality should not be construed as evidence of the benignity of the lesion. Up to 10% of breast cancers are radiographically occult. Thus, a lesion should be removed if it meets the criteria for biopsy based on the clinical breast examination, regardless of the breast imaging characteristics. Likewise, if a woman identifies an area of change in her breasts, the complaint should be taken seriously.

In addition to highly suspect lesions, referral to a breast (general) surgeon should be considered for an additional small subset of patients. Masses in prepubertal or pubescent girls (prepubertal gynecomastia) could represent the forming breast buds and must not be sampled for biopsy unless highly suspect because lifelong cosmetic deformity may result. Masses greater than 4 cm are best approached by core biopsy provided that if the lesion proves to be malignant, consideration should be given to neoadjuvant chemotherapy. In addition, if the lesion is benign, special surgical techniques will be necessary to minimize the cosmetic deformity associated with subsequent removal. Finally, biopsy of lesions requiring preoperative mammographic localization with wire placement should be performed by physicians who have received specific training in this technique.

Consideration should be given to performing fine-needle aspiration (FNA) before core or excisional biopsy (see Chapter 226, Fine-Needle Aspiration Cytology and Biopsy). FNA is both diagnostic and therapeutic for simple cysts, thereby avoiding unnecessary anxiety and surgery. If the mass is solid, a specimen for cytologic examination can be obtained, and breast cancer can be diagnosed before excisional biopsy. The false-negative rate of FNA is 0.4% to 35% and the false-positive rate is less than 1%. Thus, concordance among the clinical breast examination, the breast imaging, and the FNA (the triple test) must be established, especially if the decision is made not to proceed to biopsy.