Evaluation of breast mass

Overview 
Theory 
Emergencies 
Diagnosis 
Resources 

Increased public awareness of breast cancer has led to a significant proportion of women presenting to clinicians with palpable masses. Breast cancers that are detected clinically or by breast self-exam are typically of more advanced stage.[31] Masses identified on mammography may undergo further evaluation with ultrasonography to determine whether they are cystic or solid. Mammographic screening has led to more breast cancers being detected at a nonpalpable stage.[32][33]

History

The median age at breast cancer diagnosis in women is 63 years.[34] The majority of breast cancers are sporadic (i.e., in patients without a family history of breast cancer).

Approximately 5% to 10% of all breast cancers are diagnosed in patients with a mutation in the BRCA-1 or BRCA-2 genes.[35] Pathogenic variants in BRCA-1 and BRCA-2 are associated with a high risk of breast cancer, with odds ratios of 7.62 (95% CI, 5.33 to 11.27) and 5.23 (95% CI, 4.09 to 6.77), respectively.[36] BRCA-1 and BRCA-2 mutations are more common in women with a family history of: breast cancer before age 50 years, bilateral breast cancer, breast and ovarian cancer in the same relative, male breast cancer, multiple cases of breast cancer in the family, one or more family members with 2 primary types of BRCA-related cancer (e.g. ovarian cancer) and Ashkenazi Jewish ancestry.[37] Therefore family history should include any family members with cancer, their primary cancer site, whether the affected relative had multiple primary cancers, age at diagnosis, age at death and sex. US Preventive Services Task Force. BRCA-related cancer: risk assessment, genetic counselling and genetic testing. 2019 Opens in new window

Prior biopsy history of atypical hyperplasia carries a four- to fivefold increase in the risk of developing breast cancer.[38][39] For those with a history of lobular carcinoma in situ (LCIS), there is a seven- to 12-fold increase in risk.[40] Patients diagnosed with an invasive cancer have a risk of contralateral breast cancer that is estimated at 0.5% to 1% a year, cumulative over their lifetime.[40]

In postmenopausal women, hormone replacement therapy with an estrogen alone is associated with little or no change in the risk of breast cancer.[41] An estrogen prescribed in combination with a progestin is associated with an increase in the incidence of breast cancer.[41][42][43][44][45][46]

There is an association between increased breast density (categorized by Breast Imaging Reporting and Data System [BI-RADS]) and breast cancer incidence in women over the age of 65 years; however, the mechanisms underlying the observed association are not yet clear.[47]

Physical exam

Findings on physical exam alone cannot definitively establish a mass as benign or malignant. However, irregular fixed masses are suspicious for malignancy.[48] Malignant lesions may also be associated with skin thickening (e.g., peau d'orange) or nipple changes.[3] A complete bilateral breast exam including assessment of the axillae and regional lymph nodes, should be performed to look for:[49]

Variation in breast size[Figure caption and citation for the preceding image starts]: Patient with inflammatory breast cancer who presented with a shrinking breastCourtesy of Dr Anees Chagpar [Citation ends].
Fungating masses[Figure caption and citation for the preceding image starts]: Obvious mass with skin involvement on right breastCourtesy of Dr Anees Chagpar [Citation ends].[Figure caption and citation for the preceding image starts]: Obvious mass with skin involvement on left breastCourtesy of Dr Anees Chagpar [Citation ends].
Dimpling or retraction of the skin[Figure caption and citation for the preceding image starts]: Patient with large breast mass and retraction at 6 o'clock of left breast, noted on elevating armsCourtesy of Dr Anees Chagpar [Citation ends].
Nipple inversion or excoriation (classic finding of Paget disease of the breast).[Figure caption and citation for the preceding image starts]: Excoriation of the nipple in a patient with Paget diseaseCourtesy of Dr Anees Chagpar [Citation ends].

These findings may be accentuated by having the patient stretch her arms over her head. Similarly, having patients place their hands on their hips and squeeze inward while flexing the pectoral muscles may reveal chest wall involvement.

The lymph nodes draining the cervical, supraclavicular, and infraclavicular fossae should be evaluated. A comprehensive exam necessitates evaluation of the patient both seated upright and lying supine, as masses are often more readily appreciated in one position than the other.

One randomized controlled trial found that encouraging documentation of the physical exam using a dedicated form resulted in a higher rate of further evaluation of breast masses and an improved cancer detection rate.[50] These results indicate that a focused physical exam can result in performance improvement.

Mammography

US guidelines recommend that all women ≥30 years old presenting with a breast mass should have a diagnostic mammogram (with additional views such as spot compression, magnification, or tangential) and digital breast tomosynthesis (or contrast-enhanced mammography if available) plus an ultrasound.[19][51] Multifocal or multicentric disease should be noted.

In the setting of a palpable breast mass, mammography is 82% to 94% sensitive and 55% to 84% specific for detecting breast cancer.[52][53][54][55]

In women <30 years with a palpable breast mass and findings on ultrasound that are suspicious for malignancy, US guidelines recommend mammography and digital breast tomography as subsequent imaging studies.[19][51]

Radiologists often characterize the findings on ultrasound or mammography according to the BI-RADS.[56][57] Some have advocated recording breast density and hormone therapy use, as these significantly affect mammography performance.[58][59][Figure caption and citation for the preceding image starts]: Breast Imaging Reporting and Data System (BIRADS) criteriaCourtesy of Dr Anees Chagpar [Citation ends]. com.bmj.content.model.assessment.Caption@5eaa63a1 [Figure caption and citation for the preceding image starts]: Magnification view demonstrating irregular spiculated mass with associated calcificationsCourtesy of Dr Nancy Pile, University of Louisville; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Screening mammogram demonstrating breast massCourtesy of Dr Nancy Pile, University of Louisville; used with permission [Citation ends]. com.bmj.content.model.assessment.Caption@2ddfcf32

BIRADS was developed by the American College of Radiologists as a standard of comparison for rating mammograms and breast ultrasound images.[57] It sets up a classification for level of suspicion (LOS) for the possibility of breast cancer. A score of 1 to 2 allows the patient to resume routine screening; a score of 3 may require further imaging with mammography and/or ultrasound scan, or short-term follow-up; a score of 4 to 5 requires a tissue biopsy.[19][57] A negative imaging study of a palpable mass also requires surgical follow-up. A score of 6 is given only after a biopsy has been examined and found to be cancerous, in which case treatment is required.[57]

Ultrasound of the breast

Ultrasonography is often considered the initial diagnostic test of choice in patients <30 years old, because the density of breast tissue in younger women limits the sensitivity of mammography.[3][51][60][61] The false-negative rate for mammography has been reported to be as high as 52% in patients <35 years old with a palpable malignant breast mass.[62]

Ultrasound is usually performed in addition to mammography in the assessment of older women with suspected breast cancer.[19][63] Ultrasound may be used as the initial diagnostic test in women aged 30-39 years where a simple cyst is suspected and the risk of breast cancer is low.[19]

Ultrasound is routinely available in the outpatient setting and is a ready extension of the physical exam. The American College of Radiology has published guidelines that may aid physicians in the performance of breast ultrasound.[60][64]

Ultrasound may identify simple or complex cyst architecture.[51] Simple cysts are smooth, round, well-demarcated, fluid-filled lesions, and are anechoic. If they have no internal septations or debris, they may simply be followed. Ultrasound is not able to detect microcalcifications in the breast.[Figure caption and citation for the preceding image starts]: Ultrasonographic image of a simple cystCourtesy of Dr Lane Roland, University of Louisville; used with permission [Citation ends]. com.bmj.content.model.assessment.Caption@7cc44f7c

Suggested management for patients with "probably benign" masses on breast ultrasound includes:[19]

Observation if clinical suspicion is low, with clinical examination and imaging with ultrasound or mammogram at 6, 12 and 24 months, to document stability.
Core needle biopsy to make a definitive diagnosis while leaving the lesion in situ. If the result is benign and concordant, a clinical breast exam every 6 to 12 months is recommended, with or without ultrasound or mammogram for 1 year to evaluate stability.
Surgical removal of the mass, particularly if the lesion is bothersome to the patient.

Ultrasonography of the axilla may also be performed to evaluate lymphadenopathy, and abnormal lymph nodes biopsied.[Figure caption and citation for the preceding image starts]: Diagnostic algorithm for breast ultrasoundCourtesy of Dr Anees Chagpar [Citation ends]. com.bmj.content.model.assessment.Caption@75044226

Magnetic resonance imaging (MRI) of the breast

National Comprehensive Cancer Network (NCCN) guidelines recommend considering MRI with and without contrast to investigate for inflammatory breast cancer if a patient has skin changes consistent with serious breast disease and is in BIRADS category 1-3, or is in BIRADS category 4-5 and has had a benign core needle biopsy.[19] MRI can also be used to evaluate suspicious nipple discharge without a palpable mass if mammography and ultrasound findings are BIRADS 1-3.[19]

The European Society of Medical Oncology recommends breast MRI for investigating suspected breast cancer if there are diagnostic uncertainties following breast ultrasound and mammography.[63]

The US Preventive Services Task Force concludes that there is insufficient evidence to determine the balance of benefits and harms of supplemental screening for breast cancer with MRI (or with breast ultrasound) in women identified to have dense breasts on an otherwise negative screening mammogram.[65]

The American College of Radiology does not recommend MRI in the initial evaluation of a patient with a breast mass.[51]

For patients undergoing MRI, diffusion-weighted imaging may be superior to contrast-enhanced MRI in differentiating benign from malignant lesions.[66] Biopsy is indicated for any suspicious lesion on MRI.

Breast aspiration and biopsy

A definitive diagnosis of breast carcinoma requires a breast biopsy. Three main types of biopsies are commonly performed.

Fine-needle aspiration (FNA): involves placing a 22- to 25-gauge needle into the breast mass and extracting cells. Increasing the number of passes increases the diagnostic odds ratio of FNA.[67] The cells can then be placed on a slide or made into a cell block. The advantages of FNA are that it is fast and easy to perform and it can be done in the doctor's office setting. The disadvantages are that it does not show histologic architecture, and it cannot help differentiate ductal carcinoma in situ from invasive malignancy. However, in the hands of an experienced cytopathologist, this technique may help distinguish benign from malignant lesions and is valuable for evaluating axillary lymph nodes.[67][68]
Core-needle biopsy: using an 8- to 14-gauge needle, provides a larger tissue sample than FNA. It can be performed by palpation, under stereotactic control, or by ultrasound guidance. This technique can be done in the doctor's office, is relatively fast and easy to perform, and allows for a histologic diagnosis. In the event of a malignant diagnosis, hormone receptor studies may be conducted on needle biopsy specimens. A variety of devices can be used to obtain these specimens, some using vacuum assistance, others radiofrequency energy.[69][70] In general, core needle biopsy is the method of choice for histologic diagnosis of breast masses.[71]
Excisional biopsy: entails removing the entire breast mass for an accurate histologic diagnosis. This invasive technique, in the case of a benign asymptomatic mass, may be unnecessary; and in the case of a malignant mass, it may not obviate the need for a second procedure to treat the cancer once a diagnosis is made. Needle biopsy findings of atypical hyperplasia or radial scars require excisional biopsy to rule out concomitant malignancy.[Figure caption and citation for the preceding image starts]: Breast biopsy techniques (FNA; fine needle aspiration)Courtesy of Dr Anees Chagpar [Citation ends].

Painful cysts

May be aspirated under ultrasound guidance. Aspirated cyst fluid should not be sent for cytology, because, with the exception of bloody cystic fluid, malignant cells are generally not identified.[72]

Cysts that recur or do not completely resolve with aspiration should be biopsied to rule out malignancy. Similarly, biopsy should be considered in complex cysts or those with solid elements. Sonographic characteristics may classify a solid mass as either "probably benign" or "suspicious." Masses that are smooth, oval, lobulated, with clearly defined margins, and that are wider than they are tall, are often benign (e.g., fibroadenoma). If a mass is irregular, heterogeneous, has poorly defined or spiculated margins, and is taller than it is wide, it is considered "suspicious" for malignancy, and biopsy should be undertaken.[Figure caption and citation for the preceding image starts]: Ultrasonographic image of a complex cystCourtesy of Dr Lane Roland, University of Louisville; used with permission [Citation ends]. com.bmj.content.model.assessment.Caption@66865b73 [Figure caption and citation for the preceding image starts]: Ultrasonographic image of a fibroadenomaCourtesy of Dr Lane Roland, University of Louisville; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Ultrasonographic image of an invasive carcinomaCourtesy of Dr Lane Roland, University of Louisville; used with permission [Citation ends]. com.bmj.content.model.assessment.Caption@55033897

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