e6-15: The Palpable Breast Mass

Palpable breast masses may be detected by a patient during breast self-examination or may be identified by the provider during a routine physical examination. A breast mass may be a presenting symptom of breast cancer, and thus a thorough work-up of any palpable breast mass is essential, regardless of age and personal risk factors for breast cancer (see Chapter 17-07). Benign causes of palpable breast masses include fibroadenomas, cysts, and hamartomas.

A. Symptoms and Signs

Clinicians should ask patients about temporal changes in the mass shape and size, as well as associated symptoms, including pain, skin thickening, and nipple discharge. A patient’s personal risk for breast cancer should be assessed, including age, previous breast biopsies, family history, and age at menarche and first pregnancy.

The location of the mass should be described using the clock-face position and distance from the nipple, as this aids the radiologist in the diagnostic evaluation. Clinicians should note the size, site, mobility, and texture of the mass, as well as areas of skin dimpling, retraction, or erythema. A thorough examination of the axillary and supraclavicular lymph node areas is essential. Some women may have areas of indeterminate thickening in the absence of a discrete and well-defined palpable mass; if this finding is asymmetric, it should be evaluated further with diagnostic imaging.

B. Diagnostic Tests and Imaging

As noted above, all women with a dominant palpable breast mass require diagnostic imaging. Approved imaging techniques include diagnostic mammography, DBT, and ultrasonography. Diagnostic mammography consists of the standard views that are used in screening mammography plus additional views, such as spot-compression and magnification, to better delineate the area of concern. Unlike in screening mammography, diagnostic radiologists are typically present in real time during diagnostic mammography to guide the need for additional views. DBT provides a three-dimensional view of the breast and may be used in place of diagnostic mammography in centers that offer this imaging technique. The breast ultrasound is the most sensitive test for distinguishing a cystic from a solid lesion and also provides detailed information regarding the shape, borders, and acoustic properties of an identified mass. In addition, ultrasonography can be used to guide the biopsy of suspicious lesions.

For women under the age of 30, ultrasonography is the initial diagnostic test of choice because the dense breast tissue found in younger women limits the sensitivity of mammography. Diagnostic mammography or DBT should be performed in women aged 40 or older with a palpable breast mass. In women between the ages of 30 and 39, ultrasonography is the preferred initial imaging test, although diagnostic mammography or DBT can be considered in high-risk patients (according to physical examination findings or clinical risk factors). Combining ultrasonography with diagnostic mammography may increase the sensitivity of testing; some benign palpable masses may only be visualized on ultrasound.

The differential diagnosis of palpable masses includes benign etiologies, such as simple cysts, fibroadenomas, hamartomas, and phyllodes tumor. Breast cysts are common, affecting nearly one-third of women aged 35–50 years. Breast cancer, including ductal carcinoma in situ, invasive lobular carcinoma, and invasive ductal carcinoma, can also initially present with a palpable breast mass. Certain history and physical examination features may be suggestive of a particular diagnosis. Patients with phyllodes tumor may report rapid growth of a large, painless breast mass. Fibroadenomas typically affect women between the ages of 20 and 40 years and present as firm, nontender, and mobile masses on physical examination. Cysts are solitary, smooth, and firm and are associated with changes in the menstrual cycle.

A. Women Younger Than 30 Years

In this age group, management of the palpable breast mass depends on the clinician’s suspicion for malignancy as well as the results of the initial ultrasound. Masses with a low likelihood of malignancy in the setting of a normal ultrasound do not require any additional radiologic testing. Highly suspicious masses that appear normal on ultrasound should be further evaluated with diagnostic mammography or DBT.

Simple cysts can be followed expectantly, whereas a complex cyst may require additional evaluation with fine-needle aspiration and cytology or with biopsy. Cysts can be categorized as probably benign, suspicious, or highly suspicious based on their ultrasound characteristics. Again, if clinical concern for malignancy is high, even patients with probably benign findings on ultrasound (or mammogram) should be referred for biopsy. All patients with suspicious or highly suspicious findings require biopsy.

B. Women Aged 30–39 Years

In women between the ages of 30 and 39, the imaging modalities may include ultrasonography, diagnostic mammography, or DBT. Ultrasonography may be more sensitive than mammography in this age group, and so may be the preferred first test. However, women with significant risk factors for breast cancer or a worrisome physical examination should be initially referred for diagnostic mammography or DBT.

If the results of the initial ultrasound are normal and there is a low likelihood of malignancy, no additional radiologic evaluation is necessary. Suspicious masses that are detected by ultrasonography require follow-up imaging with bilateral mammography.

Women who undergo diagnostic mammography or DBT as the initial imaging test and are noted to have a mass with benign features should have a breast ultrasound performed for correlation. The results of that ultrasound, as well as clinical suspicion, dictate the need for further imaging. When ultrasound findings suggest a benign mass, patients may be monitored clinically or may require short-term radiologic follow-up. In contrast, patients with suspicious findings should be referred for biopsy.

C. Women Aged 40 Years and Older

Diagnostic mammography and DBT are the initial tests of choice in women age 40 years and older with a palpable breast mass. If the mammography or DBT results are negative, benign, or probably benign, then additional management depends on clinical suspicion and breast ultrasound results. In the setting of a low clinical suspicion for malignancy, masses with negative ultrasound results can be monitored closely. Conversely, in the setting of worrisome history or physical examination findings, tissue biopsy should be pursued even if both mammogram and ultrasound are normal.

The management of simple cysts in women age 40 years and older is similar to that in younger women. Solid masses that are classified as probably benign on mammogram and ultrasound should be monitored very closely if clinical suspicion is low but otherwise referred for biopsy. Biopsy is recommended to evaluate any mass that appears suspicious or highly suspicious on ultrasound or diagnostic mammogram.

Certain benign breast masses may be classified as nonproliferative (breast cysts, ductal ectasia) or proliferative (sclerosis, adenosis, radial scars, ductal hyperplasia, intraductal papilloma). Proliferative lesions are associated with a slightly increased risk of subsequent breast cancer diagnosis, although the absolute risk is low in most patients.

• All patients with suspicious or highly suspicious masses on diagnostic imaging (diagnostic mammography, DBT, or ultrasonography) should undergo breast biopsy, regardless of age.

• Even when diagnostic mammogram and ultrasound are normal, all women should be referred to a breast specialist if clinical suspicion for malignancy is high.