Breast Mass / Breast Nodule

A breast mass:
- Is a nodule or growth of tissue:
  - That represents an aggregation of coherent material
A breast mass:
- May be benign or malignant:
  - A benign mass:
    - May be solid or cystic
  - A malignant mass:
    - Is typically solid
    - A cystic mass with solid components (complex cyst):
      - Can also be malignant
Evaluation of a palpable breast mass:
- Requires a systematic approach to the history, physical examination, and radiographic imaging studies to ensure a correct diagnosis:
  - A missed diagnosis of breast cancer is one of the most frequent causes of malpractice claims in the United States
A breast mass:
- Can be discovered by the patient incidentally or on routine examination by a patient or clinician:
  - It is often discovered after a breast examination prompted by other symptoms (eg, pain, nipple discharge) or trauma
On the physical examination:
- The palpable breast mass can be obvious or subtle
- The density can be soft, firm, or hard
- It can be mobile or fixed to the chest wall or skin
- It can be tender or nontender
- The mass may have well-defined or nondiscrete margins
- The mass can be associated with clinical findings including:
  - Ecchymosis
  - Erythema
  - Peau d’orange
  - Skin dimpling
  - Nipple discharge
  - Nipple retraction
- Often the mass has no associated clinical findings
Multiple epidemiologic studies around the world have reported that:
- Breast cancer occurs more frequently in the upper outer quadrant than any other part of the breast:
  - In a National Cancer Database (NCDB) study of over 2 million women diagnosed with breast cancer between 2004 and 2015:
    - 39.5% had cancer in the upper outer quadrant
  - Smaller studies reported breast cancer in the upper outer quadrant in 36% to 62% of patients
  - Although this is most likely secondary to:
    - The upper outer quadrant having more breast tissue:
      - There may be differences in genomic instability in this area
The differential diagnosis of a palpable breast mass includes:
- Benign and malignant etiologies
Palpable breast masses:
- Are very common in women
- Most palpable masses are benign:
  - Approximately 90% or more of palpable breast masses in women in their 20s to early 50s are benign:
    - However, excluding breast cancer is a crucial step in the assessment of a breast mass in a woman of any age
The following types of masses are among the most common benign breast masses palpated:
- Fibroadenoma:
  - A simple fibroadenoma is a benign solid mass
  - It typically is identified in young women but can also be identified as a calcified mass in older women
  - The mass is firm and often mobile
  - A fibroadenoma may be:
    - Solitary
    - Multiple
    - Bilateral
- Cyst:
  - A simple cyst is a benign, fluid-filled mass:
    - That can be palpated as a component of fibrocystic changes of the breast or as a discrete, compressible, or ballotable solitary mass
  - Breast cysts are commonly found in premenopausal, perimenopausal, and occasionally postmenopausal women
- Fibrocystic changes:
  - Fibrocystic changes in the breast are common:
    - Particularly in premenopausal women
  - May be prominent and organized:
    - However, the breast tissue tends to be more diffuse and tender and generally does not form a discrete or well-defined mass
  - Most patients present with breast pain:
    - That may be cyclical or constant
    - May be bilateral, unilateral, or focal
  - The breast tissue, particularly in the upper outer quadrant:
    - May increase in size prior to the onset of menses, then return to baseline after the onset of the menstrual flow
  - On clinical examination:
    - The breast tissue frequently is nodular
- Galactocele:
  - A galactocele is a milk retention cyst common in women who are breastfeeding
- Fat necrosis:
  - Fat necrosis is a benign breast mass that can develop after:
    - Blunt trauma to the breast
    - Injection of native or foreign substances such as:
      - Fat, paraffin, or silicone
    - An operative procedure such as breast reductive surgery or autologous breast reconstruction
    - Radiation therapy to the breast
  - Fat necrosis from trauma:
    - Is generally associated with skin ecchymosis
  - Fat necrosis can often be clinically and even radiographically difficult to distinguish from a malignant mass
- Breast abscess:
  - A breast abscess is a localized collection of inflammatory exudate (ie, pus) in the breast tissue
  - Primary breast abscesses:
    - Develop when mastitis or cellulitis is left untreated or does not respond to antibiotic treatment
    - Patients with primary breast abscess present with:
      - Localized, painful inflammation of the breast associated with fever and malaise, along with a fluctuant, tender, palpable mass
  - The diagnosis is established via ultrasonography demonstrating a fluid collection
- Malignant:
  - The differential diagnosis of a malignant breast mass includes:
    - Multiple invasive and noninvasive cancers
  - The following types of masses are among the most common malignant breast masses palpated:
    - The most common breast cancer is an infiltrating ductal breast carcinoma:
      - This invasive histology accounts for approximately 70% to 80% of invasive breast cancers
    - Other invasive breast cancers include infiltrating lobular carcinoma and mixed ductal / lobular carcinoma:
      - Infiltrating lobular carcinoma often presents as a prominent diffuse thickening of the breast rather than as a discrete mass
      - There are also variants of the invasive ductal carcinomas that can be detected as a palpable mass
      - Rarely, noninvasive cancers (ductal carcinoma in situ [DCIS]) with or without microinvasion can develop into a palpable breast mass
The clinical evaluation of a palpable breast mass begins with a complete history and physical examination:
- Although some radiographically identified masses may not be palpable, the same clinical evaluation also applies
History:
- The history should include a:
  - Full review of medical and surgical illnesses, medications, and allergies and an assessment of risk factors for breast cancer, such as a detailed family history
  - In addition, for masses identified by the patient, subjective information about how and when the mass was first noted, if it is painful, and how it has changed over time should be recorded
- The history of presenting symptoms includes:
  - Any change in the general appearance of the breast, such as an increase or decrease in size or a change in symmetry
  - New or persistent skin changes
  - New nipple inversion
  - If nipple discharge is present, whether it is bilateral, unilateral, or from one specific duct
  - Other important information includes the timing, color, frequency, and spontaneity of the discharge
  - The characteristics of any breast pain, the relationship of symptoms to menstrual cycles (cyclic or noncyclic), the location within the breast (or both breasts), the duration, and whether it is aggravated or alleviated by any activities or medications
  - The presence of a breast mass and its evolution, including how it was first noted (accidentally, by breast self-examination, clinical breast examination, or mammogram), how long it has been present, and whether it has changed in size
  - The precise location of any breast mass
  - Whether a mass waxes and wanes during the menstrual cycle:
    - Benign cysts may be more prominent premenstrually and regress in size during the follicular phase
  - Trauma to the breast (eg, car accident with seat belt, direct injury from a hard object) may result in a breast mass due to the development of fat necrosis or a hematoma
  - In addition, trauma may be the precipitating event to detection of an existing benign or malignant mass:
    - Any mass after a trauma that fails to resolve will require a complete evaluation
- Risk factors for breast cancer:
  - A thorough risk assessment is part of the evaluation of women with breast complaints, and significant negative as well as positive findings should be documented in the medical record
Physical examination:
- The breast examination includes both breasts and the nodal basins of the neck, chest wall, and both axillae and is part of a complete physical examination:
  - Inspection – The patient should be examined in both the upright and supine positions. The patient must be disrobed from the waist up, allowing the examiner to visualize and inspect the breasts
  - The breast examination is started with the patient in a seated position with her arms relaxed
  - The patient is then asked to raise her arms over her head so the lower part of the breasts can be inspected
  - Finally, the patient should put her hands on her hips and press in to contract the pectoral muscles so that any other areas of retraction can be visualized
  - Inspection of the breast includes:
    - Asymmetry – Observe the breast outline and contour for any bulging areas
    - Skin changes – Check for dimpling or retraction, edema, ulceration, erythema, or eczematous appearance, such as scaly, thickened, raw skin
    - Nipples – Assess for symmetry, inversion or retraction, nipple discharge, or crusting
  - Palpation – After careful inspection, proceed with the palpation of regional lymph nodes and the breasts
    - Regional lymph node examination – While the patient is sitting, the regional lymph nodes are examined, with attention to the cervical, supraclavicular, infraclavicular, and axillary nodal basins:
      - The best examination of the axillary nodes requires that the patient relax her shoulders and allow the examiner to support her arm while the axilla is palpated
      - This allows relaxation of the latissimus and pectoralis muscles for ease in palpating high into the axilla
      - It is important to note the presence of any palpable nodes and their characteristics, whether they are soft and mobile or firm, hard, tender, fixed, or matted
    - Breast examination – A bimanual examination of the breasts is performed while the patient is still in the sitting position, supporting the breast gently with one hand and examining the breast with the other hand
    - The examination is completed with the patient in a supine position, with the ipsilateral arm raised above her head:
      - This allows the examiner to flatten the breast tissue against the patient’s chest
      - It is sometimes useful to have the patient roll onto her contralateral hip to flatten the lateral part of the breast
    - The entire breast must be examined, including the breast tissue that comprises the axillary tail of Spence, which extends laterally toward the axilla
    - To be sure that all breast tissue is included in the examination, it is best to cover a rectangular area bordered by the clavicle superiorly, the midsternum medially, the midaxillary line laterally, and the lower rib cage inferiorly
    - The examination technique should be systematic, using concentric circles, a radial approach, or vertical strips
    - Palpation should be done with the finger pads rather than the fingertips
    - Circular motions with light, medium, and deep pressure ensure palpation of all levels of breast tissue
    - One hand stabilizes the breast while the other hand is used to perform the examination
Documentation:
- The location of the mass as well as any abnormality found on examination should be accurately documented
- The size of any mass should be measured in centimeters and its location, mobility, and consistency recorded
- It is helpful to record the location of any abnormality by documenting both the position on the breast and the distance in centimeters from the areola:
  - In this manner, the precise location can be easily identified on subsequent follow-up examinations by the initial examiner as well as other practitioners
- The “clock” system can be used for documentation, comparing the breast to a clock and using the location on the clock to indicate the location of a lesion (eg, 1 o’clock position)
- The entire examination should be clearly and completely documented in detail, including significant negatives, even if it is completely normal. Distance from the nipple or from the radial edge of the areola can be used to document location of the mass
Timing of examination:
- In premenopausal patients:
  - The breast examination is best performed when hormonal stimulation of the breasts is minimized:
    - Which is usually seven to nine days after the onset of menses in premenopausal women:
      - However, the evaluation of a clinically suspicious mass should not be influenced by the phase of the menstrual cycle
Accuracy of examination :
- The physical examination of patients with benign breast disease parallels the examination of patients with cancer since normal breast tissue in women is often somewhat nodular
- The first goal of the physical examination is to determine whether a dominant mass, thickening, or asymmetry is present:
  - This is particularly important in younger women, whose breasts are more likely to be generally nodular than older women:
    - In a retrospective review of 605 women under the age of 40 years who were referred to a breast clinic for evaluation of a breast mass:
      - A dominant mass was palpated by the surgeon in 36% of self-detected masses (n = 484) and 29% of clinician-detected masses (n = 121)
- However, the physical examination findings cannot always distinguish between a benign mass and a malignancy, even for clinical experts, as the findings may be subtle
- Studies that have examined the usefulness of the physical examination for diagnosing benign versus malignant breast masses have found that clinicians can often make the right diagnosis but are not perfect:
  - In one report, from a study of symptomatic women, experienced examiners who diagnosed “definite cancer” on palpation were correct in 93% of cases
  - In another series, the physical examination had a positive predictive value of 73% and a negative predictive value of 87%
Diagnostic evaluation:
- Imaging options include diagnostic mammography, including tomosynthesis where available, and targeted breast ultrasound, the choice of which depends on patient age and the degree of clinical/radiologic suspicion
- There is little role for advanced imaging modalities such as breast magnetic resonance imaging
The diagnosis of a benign or malignant breast mass is confirmed by a breast biopsy:
- The definitive diagnosis of a benign or malignant breast mass is based upon the histopathology from a core, incisional, or excisional tissue biopsy or a fine needle aspiration (cytologic evaluation)
The appropriate interval of follow-up for patients with benign biopsy is controversial and depends on the histology:
- Although various intervals (four or six months) have been proposed, no evidence-based guidelines are available to aid this decision
- For patients with a benign biopsy:
  - I suggest repeating clinical examination and imaging every six months for two years, and if stable, patients may return to routine screening after that
  - Biopsy-proven benign masses that change clinically or radiographically, such as increasing in size on follow-up examinations, should be reevaluated and excised.
Whether a short follow-up interval is necessary has been questioned:
- A study using the Breast Cancer Surveillance Consortium (BCSC) registry compared cancer detection rates and stage for patients with short-interval follow-up (three to eight months) with those who returned to routine screening (9 to 18 months) following benign core breast biopsy (stereotactic or ultrasonography guided):
  - A total of 17,631 biopsies with benign findings were identified
  - Similar cancer detection rates were found for the short-interval follow-up and routine screening groups with no significant differences in stage, tumor size, or nodal status
  - Thus, it may be safe for those with a benign radiologic-pathologic-concordant percutaneous breast biopsy to return to routine screening
  - However, the study did not identify the spatial relationship between the finding that prompted the initial biopsy and the site of the subsequent cancer (which could have represented a false-negative result)