Physical Examination
A clinical breast examination should be performed for all women presenting with a breast lump. Most often, the patient's referring provider or breast specialist has performed a thorough examination of both breasts. However, the breast imager should be familiar with the performance of the breast examination and ideally should perform a focused examination targeted at the area of concern to assess concordance between the imaging findings and the clinical examination findings [
17].
At physical examination a dominant mass should feel different from surrounding breast parenchyma and should feel asymmetric compared with the contralateral breast. Masses suggestive of malignancy are more likely to be firm, immobile, and fixed to the surrounding breast tissue or skin (as evidenced by skin dimpling or nipple retraction) and to have indistinct margins [
7]. Benign masses are more likely to be mobile and have smooth, well-defined margins. Normal structures that can be mistaken for a breast mass include a prominent rib, costochondral junction, prominent fat lobule, or discrete ridge of normal fibroglandular tissue.
The focused clinical examination allows the imager to ensure that the correct site is being evaluated at targeted ultrasound. It also allows assessment of concordance between the imaging and physical examination findings. Determining concordance should include comparison of location, size, shape, and margin of the palpable lesion with any potential corresponding lesion identified at imaging. If the lesion cannot be felt at imaging, then the previous description by the patient or referring provider should be used to direct the imaging and concordance evaluation.
Mammography
Mammography is recommended as the first imaging modality in the evaluation of palpable breast findings in women 40 years old and older. A radiopaque marker should be placed over the site of clinical concern. If the patient has undergone recent (≤ 6 months) bilateral mammography, only ipsilateral mammography is indicated. In addition to craniocaudal and mediolateral oblique whole-breast mammographic views of the affected breast, spot compression and magnification views are typically obtained of the area of clinical concern.
If mammography reveals a clearly benign cause of the palpable abnormality, such as a calcified involuting fibroadenoma, lymph node, lipoma, hamartoma, galactocele, or oil cyst, or if only fatty tissue is present in the area of concern, no further imaging is needed. For all other mammographic findings, including masses with probably benign or suspicious features, further evaluation with targeted ultrasound is indicated.
Normal mammographic findings are not sufficient to rule out malignancy in a nonfatty breast. If there is no mammographic finding at the site of the palpable lump, further workup with targeted ultrasound is required. Approximately 13% of women with palpable breast cancer have normal mammographic findings [
18]. False reassurance from a normal mammogram can lead to a delay in cancer diagnosis. One study [
19] showed that among women with a palpable breast mass and normal mammographic findings, only 57% of women received adequate complete evaluation. In another study [
20], in which the participants were women with self-detected palpable breast lumps, 32% of women with cancer and normal mammographic findings had delayed diagnoses.
Ultrasound
Historically, use of breast ultrasound was limited to differentiating cysts from solid masses [
21]. It was otherwise thought that ultrasound had little or no place in the evaluation of palpable breast masses [
7]. With technologic advances, ultrasound has become an essential part of managing palpable breast masses [
3,
4,
22–
24]. It is the primary imaging modality for women younger than 40 years presenting with a palpable breast mass and is a critical adjunct to mammography for older patients. A woman with a palpable lump corresponding to a clearly benign finding at targeted ultrasound, such as simple cyst, nonpathologic lymph node, lipoma, sebaceous cyst, clustered microcysts, or duct ectasia, can safely undergo clinical follow-up without short-interval imaging follow-up, needle aspiration, or biopsy.
The addition of ultrasound to the evaluation of palpable breast lumps improves cancer detection. One study [
22] showed that 11% of palpable breast cancers were visible at ultrasound but were mammographically occult. Similarly, use of targeted ultrasound was found to increase cancer detection by 14% in patients with symptoms who were evaluated with both mammography and ultrasound [
23]. When both mammographic and ultrasound findings are negative in the evaluation of a palpable breast mass, the negative predictive value is high, ranging from 97% to 100% [
3,
4,
23–
26]. Reported values in the literature are summarized in
Table 1. If combined imaging findings are negative and clinical breast examination findings are not highly suspicious, the patient may be reassured of the negative findings and safely undergo clinical follow-up with her health care provider. However, any highly suspicious mass found at clinical examination should be biopsied, regardless of negative imaging findings, because of the extremely small but present risk of malignancy.
Palpable masses may have probably benign features at targeted ultrasound (solid mass with circumscribed margins, oval shape, and horizontal orientation). Previously, the use of BI-RADS category 3 assessment with a short-term follow-up recommendation was reserved only for nonpalpable findings, as reflected in the 2003 4th edition ACR BI-RADS manual specifications [
10]. More recent evidence, however, has shown that short-term follow-up imaging is an acceptable alternative to immediate biopsy in the management of palpable lesions with probably benign ultrasound features. Rates of malignancy of palpable probably benign lesions are not significantly different from those of nonpalpable probably benign lesions [
27,
28]. The current 2013 5th edition ACR BI-RADS [
29] supports the application of probably benign assessments for palpable as well as nonpalpable breast masses.
Table 2 shows the rates of malignancy of palpable solid masses with probably benign ultrasound features, which range from 0 to 0.9% [
28,
30–
33]. Although Shin et al. [
27] reported a rate of malignancy of 3.2%, they studied a distinct subgroup of patients with probably benign lesions who proceeded to needle biopsy. Thus those authors attributed the higher cancer rate to including in their population only masses subjected to core needle biopsy rather than all probably benign masses. For this reason, the study is excluded from
Table 2. At our institution, palpable masses with probably benign ultrasound features are assessed as BI-RADS category 3. Patients are reassured of the very low risk of breast cancer and undergo follow-up by ultrasound for 2 years at 6-month intervals. Some patients prefer to undergo immediate core needle biopsy rather than follow-up, which may be a reasonable alternative for a subset of patients. In these cases, image-guided core needle biopsy is encouraged over surgical excision because of the lower costs, lower morbidity, and high diagnostic accuracy of ultrasound-guided needle biopsy compared with surgical excision.
MRI
Despite the lack of supporting evidence, MRI is still used as a problem-solving tool for evaluation of breast symptoms. One study [
34] showed that 5% (276/5769) of MRI examinations in U.S. community health care settings were performed for the indication of “persistent clinical breast concern with negative imaging.” At our institution, in a study of MRI examinations between 2003 and 2007 [
35], we found that 7% (204/3001) of MRI examinations were performed for the indication of problem solving and that a palpable lesion or other clinical finding was the most common problem-solving indication, accounting for 55%. Both of these studies concluded that breast MRI is not an appropriate imaging technique for evaluation of palpable symptoms, because it provides little added information to careful evaluation with mammography and ultrasound. In the cases in our study in which MRI was accurate for identifying malignancy in the area of clinical concern, biopsy would likely have been performed regardless of the MRI findings either because of level of clinical concern or because of suspicious mammographic or ultrasound findings. MRI also resulted in additional, unnecessary biopsies due to false-positive findings in areas distinct from the site of initial clinical concern. Furthermore, negative MRI findings can cause false reassurance and poor compliance with subsequent follow-up recommendations based on mammographic or ultrasound results [
34].
Fortunately, at our institution and others, the use of breast MRI for problem solving regarding clinical breast concerns has continued to steadily decrease each year since these studies were conducted. It now represents less than 0.5% of all breast MRI examinations performed at our institution annually. One clinical scenario in which MRI may be helpful is questioned physical examination changes at the site of a lumpectomy, for which neither mammographic nor ultrasound findings are definitive. MRI can be helpful for differentiating scar from recurrence in the specific setting of suspicious clinical examination findings with inconclusive mammographic or ultrasound findings [
36].