Breast Masses
61 BREAST MASSES
Christina A. Finlayson M.D.
1. What are the three parts of breast screening that assist in the early diagnosis of breast cancer?
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Breast self-examination (BSE) should begin at age 20 years and should be performed monthly. The breast is usually easiest to examine on the days immediately after the menstrual cycle. BSE can be frustrating to patients, particularly when they have fibrocystic changes, because they are not certain what they are feeling or supposed to feel. The BSE technique should be taught early and reinforced regularly. Women who regularly perform BSE present with tumors 1 cm or smaller more frequently than women who do not perform BSE. BSE has yet to translate into a survival benefit, however. Some women are spooked by repetitive false-positive findings. These women need to rely on their physicians to perform a breast examination once a year.
Clinical or physician breast examination (CBE) should also begin at age 20 years and should be performed annually for women at average risk for breast cancer. Although tumors between 0.5 and 1.0 cm occasionally can be detected by experienced clinicians, tumors between 1.0 and 1.5 cm are detected 60% of the time. Ninety-six percent of tumors larger than 2.0 cm are identified. CBE should be part of every primary care physician’s health maintenance and screening program.
Screening mammography has had the most substantial impact on the early diagnosis of and subsequent decrease in mortality from breast cancer.
2. When should routine mammography begin?
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When mammography screening begins at age 40 years, a 30% or greater decrease in death from breast cancer can be realized. Mammography should be performed annually thereafter.
3. Does a normal or negative mammogram result guarantee that no cancer is present?
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No. Mammography has a false-negative rate of at least 15%. For a breast cancer to be detected on mammography, it must have radiographic characteristics that differ from the surrounding tissue. Some tumors, particularly lobular carcinoma, invade breast tissue in a way that does not alter the radiograph.
4. What is the difference between a screening and a diagnostic mammogram?
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Screening mammography is done in asymptomatic women to look for clinically occult breast cancer. Two views of each breast are obtained. When a woman has a breast complaint such as a mass or an abnormal screening mammogram, diagnostic mammography is performed. A diagnostic mammogram focuses on the area of clinical concern. Additional views taken at multiple angles or compression views taken with increased magnification help to distinguish between benign and malignant changes.
5. How are mammographic abnormalities characterized?
| Bi-Rads | 0 | Requires further evaluation |
|---|---|---|
| 1 | Negative (normal examination results without any findings) | |
| 2 | Benign (normal examination results with a definitely benign finding) | |
| 3 | Probably benign (< 3% chance of malignancy) | |
| 4 | Suspicious (30% chance of malignancy) | |
| 5 | Highly suspicious or malignant |
The American College of Radiology has developed a standard interpretation score to decrease ambiguity in mammographic reporting:
* Category 0 is a temporary designation that requires further diagnostic imaging by either ultrasound or compression (magnification) views of the abnormality. After further evaluation, such mammograms are reclassified into one of the other categories.
* Categories 1 and 2 require no further evaluation; the usual mammographic schedule is not altered.
* For category 3, a short-interval (6-month) diagnostic mammogram of the affected breast is recommended. Alternatively, a biopsy may be performed.
* Categories 4 and 5 require a biopsy.
6. Which biopsy techniques aid in the diagnosis of mammographic abnormalities?
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Several image-guided biopsy techniques maximize diagnostic yield while minimizing patient discomfort and loss of normal tissue:
Tru-cut core biopsy is performed with a 14-18-gauge coring needle. Multiple tissue samples (at least seven) are obtained.
Stereotactic biopsy is performed with an 11-gauge, vacuum-assisted biopsy needle. Large-core biopsy can remove an entire lesion or area of calcification. A marking clip can be left in the breast at the site of the biopsy. Core biopsy and vacuum-assisted biopsy can be performed with local anesthesia alone.
The advanced breast biopsy instrument (ABBI) removes up to a 2-cm core of breast tissue. It requires local anesthesia and intravenous (IV) sedation and usually is performed in the operating room.
Needle localization breast biopsy is a surgical procedure that requires the radiologist to place a thin wire into the breast abnormality. In the operating room, the wire and the breast tissue surrounding the wire are removed. This procedure can be done with local anesthesia with or without sedation.
Although fine-needle aspiration (FNA) is excellent for evaluation of palpable abnormalities, its sensitivity and specificity for image-guided biopsy are not acceptable.
With the exception of FNA (which evaluates cells not intact tissue), each of these techniques is comparable in identifying the pathology associated with the mammographic abnormality. Unfortunately, a 5% false-negative rate is associated with each of these techniques.
7. What are the characteristics of a dominant breast mass?
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Identification of a dominant mass, especially in premenopausal women, can be challenging. Typically, a dominant mass can be palpated in three dimensions, and its density is palpably distinct from surrounding breast tissue. Of equal importance are nodule, lump, thickening, and asymmetry. Breast cancer cannot be excluded by physical examination alone. “Failure to be impressed by the physical examination findings” is the most common reason cited for a delay in the diagnosis of breast cancer.
8. What are the most frequently encountered palpable breast masses?
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Most dominant masses are benign. Examples include cysts, fibroadenomas, and fibrocystic masses. Carcinoma, although not the most common breast mass, is the reason that all persistent, dominant masses require a diagnosis. Other less common palpable breast masses are lipomas, granulomas, fat necrosis, epidermal inclusion cysts, and lactational adenomas.
9. What are the distinguishing characteristics of the most common palpable masses?
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A cyst is a regular, firm or fluctuant, mobile mass that may be tender. A fibroadenoma is smooth, firm, elongated (longer than it is wide), and mobile with discrete borders. Fibrocystic changes are “lumpy-bumpy” breast tissue. There may be a discrete focal area of fibrosis that is more dominant than the background irregular tissue. Carcinoma is an irregular, hard, painless mass. In advanced stages, it may become fixed to the chest wall or be associated with overlying skin changes. Lobular carcinoma often appears as a soft mass or area of thickening. Because physical examination alone is unreliable in excluding breast cancer, a biopsy must be obtained for all persistent, dominant solid masses.
KEY POINTS: BREAST MASSES
1. A cyst is a regular, firm or fluctuant, mobile mass that may be tender.
2. A fibroadenoma is smooth, firm, elongated, and mobile with discrete borders.
3. Fibrocystic changes are “lumpy-bumpy” breast tissue.
4. Carcinoma is an irregular, hard, painless mass.
10. A 32-year-old woman presents with the complaint of a breast lump. Which questions about the patient’s history are important in the evaluation of the mass?
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The size of the mass, whether it has changed in size, how long it has been present, whether it is painful, skin changes, nipple discharge, and changes in relation to the menstrual cycle are all important. Assessment of risk factors, including personal or family history of breast, ovarian, or other cancers; age at menarche; age at first full-term pregnancy; age at menopause; birth control or hormone replacement use; and history of previous breast biopsy are also important.
11. The mass identified in question 10 is discrete, not tender, easily palpable, and has gradually increased in size. What is the next step?
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Ultrasound of a discrete mass can determine if it is cystic or solid. Specific ultrasound criteria are used to define a simple cyst. A simple cyst can be aspirated or observed. A complex cyst must be further evaluated by aspiration (to see if it completely resolves) or by excisional biopsy (if it does not). A solid mass requires a tissue diagnosis.
12. How is a cyst aspiration performed?
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A 22-gauge needle is inserted into the cyst, and fluid is withdrawn. Generally, a 10-mL syringe is adequate. If the cyst is quite deep and difficult to fix between the clinician’s fingers, the aspiration can be performed under ultrasound guidance. Aspiration of a cyst is both diagnostic and therapeutic. After aspiration, the mass should resolve completely. If a mass persists or recurs after two aspirations, it should be excised. Cyst fluid may be clear or cloudy yellow, green, gray, or brown. A bloody aspirate obligates excision of the lesion.
13. What techniques are available for diagnosis of a palpable, solid breast mass?
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FNA, core biopsy, incisional biopsy, and excisional biopsy each have a role:
FNA recovers cells from the mass and requires a dedicated cytopathologist for accurate interpretation. Some (but, not all) benign and malignant lesions can be characterized accurately by FNA, but FNA cannot discriminate between invasive and in situ carcinoma. To be used effectively, it must be correlated with physical examination and breast imaging.
Core biopsy is also a sampling technique that removes 14-18-gauge pieces of tissue for histologic evaluation. Because it is a sampling, there is a risk of missing the lesion and obtaining a false-negative result. Again, correlation with physical examination and imaging is important to avoid missing a cancer.
Incisional biopsy is rarely used today. Its primary role is for a highly suspicious lesion that is a candidate for neoadjuvant treatment and that is not definitively diagnosed on core biopsy.
Excisional biopsy completely removes the target lesion. It provides the most tissue for pathologic evaluation and, in benign disease, is both diagnostic and psychologically therapeutic.
14. What is the role for breast imaging in the evaluation of a palpable breast mass?
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Breast imaging helps to define the lesion and screen the remainder of the breast for secondary lesions. In general, breast imaging is performed before biopsy because the artifact from the biopsy can interfere with the interpretation of the study.
In women younger than age 30 years, in whom the risk of malignancy is low, mammography should be reserved for the most suspicious lesions. For women older than age 30 years, evaluation of a mass suspicious for malignancy includes mammography to characterize the mass and to evaluate the remainder of the breast. Ultrasound can reliably differentiate between cystic and solid masses. It is very unusual (< 2%) that ultrasound will fail to identify a clinically significant breast mass.
15. What is the “triple negative test” or “diagnostic triad”?
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There are three components to diagnosing a palpable breast abnormality: physical examination, breast imaging, and biopsy. Benign lesions do not have to be removed, but the difficulty is in differentiating between a benign and a malignant lesion. When the characteristics of a mass on physical examination indicate low suspicion for malignancy, the mammogram is benign, and FNA recovers benign cells, the likelihood that the lesion is benign is 98%. Treatment options include excision for definitive diagnosis or observation. If observation is elected, the abnormality should be reexamined within 3 months to confirm that it is stable. If any component of the diagnostic triad is worrisome, definitive diagnosis, usually with excisional biopsy, is necessary.
References
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BIBLIOGRAPHY
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Abernathy’s Surgical Secrets, Updated Edition (Book w / Student Consult)
Author / s: Harken Alden H., Abernathy Charles, Moore Ernest Eugene
Year: 2004
Pages: 473
Publishers: Elsevier Mosby; 5th Bk & Acc edition
ISBN: 0323034160
