Ch 21 paragraph

Anatomy and Physiology

The female breast sits against the anterior thoracic wall, extending from the clavicle and second rib down to the sixth rib, and from the sternum laterally to the midaxillary line. It overlies the pectoralis major and, at its inferior and lateral margins, the serratus anterior. The glandular tissue is organized into roughly 15–20 lobes that radiate toward the nipple and areola via lactiferous ducts and sinuses. Each lactiferous duct drains a lobe composed of 20–40 lobules, which are milk-secreting tubuloalveolar glands. Adipose tissue surrounds the breast, particularly in superficial and peripheral areas. The surface of the areola features small rounded elevations formed by Montgomery glands, sweat glands, and accessory areolar glands; a few hairs are commonly seen on the areola. During pregnancy, sebaceous glands secrete an oily substance that protects the areola and nipple during lactation. The breast has two fascial layers: the superficial fascia lies just beneath the dermis, and the deep fascia lies anterior to the pectoralis major. The breast is anchored to the skin by suspensory Cooper ligaments, fibrous bands that traverse the breast and insert perpendicular to the dermis. Occasionally, extra (supernumerary) nipples occur along the milk line, usually presenting as a small nipple and areola, sometimes mistaken for a mole. If there is glandular tissue, there may be pigmentation changes, swelling, tenderness, or lactation during puberty, menses, or pregnancy and possible association with other congenital anomalies, mainly renal or thoracic. Treatment is advised if diagnostic ambiguity, cosmetic concerns, or potential pathology exists.

To describe clinical findings, the breast is divided into four quadrants using horizontal and vertical lines crossing at the nipple; a fifth area, the axillary tail of the breast or tail of Spence, extends laterally toward the anterior axillary fold. Findings can also be localized by clock-face positioning and distance from the nipple. The breast is hormonally sensitive and responds to monthly cycling and aging. The adult breast may feel soft but is often granular, nodular, or lumpy, a normal physiologic nodularity that is typically bilateral and may predominate in certain areas. Nodularity often increases before menses, when breasts enlarge and may be tender or painful. Breast texture and composition vary with age, nutritional status, pregnancy, exogenous hormones, and other factors. After menopause, there is atrophy of glandular tissue and a notable decrease in the number of lobules. For breast changes during adolescence and pregnancy, refer to related chapters. The nipple and areola contain smooth muscle that contracts to express milk, driven by neurohormonal stimulation from infant sucking. Tactile stimulation during breast examination can cause the nipple to become smaller, firmer, and more erect, and can cause the areola to pucker and wrinkle. These smooth muscle reflexes are normal and should not be mistaken for disease.

Axilla and Lymphatics

The axilla is a pyramidal space defined superiorly by the axillary vein, laterally by the latissimus dorsi, and medially by the serratus anterior. Three important nerves traverse the axilla: the thoracodorsal nerve (innervates the latissimus dorsi), the long thoracic nerve (innervates the serratus anterior), and the intercostobrachial nerve (sensory to the skin of the axilla and upper medial arm). The axillary lymph nodes are arranged into six groups along the chest wall, typically high in the axilla between the anterior and posterior axillary folds; central nodes are the most commonly palpable. Approximately three-quarters of breast lymphatic drainage goes to axillary nodes. Lymph node groups include:

• Anterior (pectoral) group: along the lower border of the pectoralis minor behind the pectoralis major; drain the lateral quadrant of the breast and superficial vessels from the anterior abdominal wall above the umbilicus.
• Posterior (subscapular) group: in front of the subscapularis; drain the back region down to the iliac crests.
• Lateral (humeral or deep) group: along the medial side of the axillary vein; drain most lymph vessels from the upper limb except superficial vessels from the lateral side.
• Central group: in the center of the axilla; receive lymph from the above three groups; include nodes in the axillary fat.
• Apical (terminal) group: at the apex of the axilla; receive efferent lymph from all other axillary nodes and are the final common pathway for axillary drainage.
• Infraclavicular (deltopectoral) group: outside the axilla in the groove between deltoid and pectoralis major; drain the lateral hand, forearm, and arm.
  Rotter’s space (Rotter’s nodes) lies between the pectoralis minor and major.

Understanding lymphatic drainage is crucial: approximately
$ext{3/4} ext{ of breast lymphatics drain to axillary nodes}.$

Male Breast

The male breast consists mainly of a small nipple and areola over a thin pad of undeveloped breast tissue with ducts. Without estrogen and progesterone stimulation, ductal branching and lobule development are limited, making male breast tissue hard to distinguish from the pectoralis muscle. Gynecomastia, benign enlargement of subareolar tissue, occurs when glandular tissue is >$2 ext{ cm}$; pseudogynecomastia is subareolar fat accumulation. Causes include increased estrogen, decreased testosterone, and medication effects. A hard, irregular, non-tender mass raises concern for cancer.

Health History: General Approach

Breast concerns may be raised during history or physical examination. Inquire about lumps, pain, or nipple discharge, the most common breast-related symptoms. If a lump or pain is reported, determine location within the breast and duration to focus the exam. Always ask whether symptoms vary with the menstrual cycle, as many benign breast conditions are hormonally influenced. This is also a good time to discuss screening guidelines. Common or concerning symptoms include a breast lump or mass, breast discomfort or pain, and nipple discharge.

Physical Examination: General Approach

A courteous, gentle approach is essential. The optimal time to examine breasts in a menstruating patient is about 5–7 days after the onset of menses because estrogen stimulation leads to swelling and nodularity before menses. For postmenopausal women and men, any time is appropriate. Nodules appearing premenstrually should be re-evaluated after menses. Patients should be told that a proper exam, especially inspection, requires full exposure of both breasts initially, though later one breast may be covered while the other is examined. Warming the hands can help, and a standardized approach is advisable for palpation, using a systematic up-and-down search pattern, varying palpation pressure, and circular fingerpad movements.

Key components for women:

• Inspect the breasts in four views: arms at the sides, arms over head, arms pressed against the hips, and leaning forward; assess skin, size, symmetry, contour, and nipple characteristics.
• Palpate the breasts for consistency, tenderness, nodules, nipple color, and any discharge.
• Inspect the axillae for rash, irritation, infection, or unusual pigmentation.
• Palpate axillary nodes for size, shape, delimitation, mobility, consistency, and tenderness.
  For men: inspect the nipple and areola for nodules, swelling, or ulceration; palpate the areola and breast tissue for nodules.

Techniques of Examination

In women, inspection and palpation are performed with the patient in the sitting position, disrobed to the waist. A thorough exam includes four views and careful inspection for skin changes, symmetry, contours, and retraction. In adolescents, breast development is assessed using Tanner stages. Views include:

• Arms at sides: note skin appearance, color, skin thickness, pore prominence (lymphatic obstruction), breast size and symmetry, contour, nipple characteristics, and any nipple discharge. Redness suggests infection or inflammatory carcinoma; peau d’orange (thickened skin and prominent pores) suggests cancer; flattening of the breast contour suggests cancer. Asymmetry due to nipple direction changes suggests underlying cancer; eczematous changes extending to the areola may indicate Paget disease with underlying carcinoma.
• Arms overhead; hands on hips; leaning forward: these positions exaggerate dimpling or retraction that may indicate cancer. Fibrous strands and skin fixation may cause inward dimpling during muscle contraction. Benign conditions such as fat necrosis can mimic some changes, but such signs require evaluation.

Palpation is best performed with the patient supine to flatten breast tissue. The exam covers a large rectangular area from the clavicle to the inframammary fold and from the mid-sternal line to the posterior axillary line, extending into the axilla to include the tail. A thorough palpation takes at least $3$ minutes per breast. Use the pads of the second, third, and fourth fingers with slightly flexed joints. The vertical strip pattern (lateral breast) is the best validated technique for detecting masses. Palpate with small concentric circles, applying light, medium, and deep pressure at each point; if the breast is large, increase pressure to reach deeper tissues. Inspect and palpate the entire breast, including the periphery, tail, and axilla. A deeply pressed rib can be mistaken for a mass.

To examine the lateral breast, the patient rolls onto the opposite hip with the hand on the forehead while shoulders stay pressed to the table; palpate starting in the axilla and move medially in vertical strips up to the nipple, then flatten the medial portion. The tail of Spence can harbor nodules that may be mistaken for enlarged axillary nodes. To examine the medial breast, the patient lies with shoulders flat and the elbow raised to shoulder height; palpate downward from the nipple to the bra line, then up to the clavicle, continuing in vertical overlapping strips to the sternum. During palpation, document:

• Tissue consistency, noting physiologic nodularity and inframammary ridge as possible benign features or mimics of tumors.
• Tenderness, especially premenstrually.
• Nodules: characterize location (quadrant or clock), size (cm), shape, consistency, delimitation, tenderness, and mobility relative to skin, fascia, and chest wall. Gently move the breast near a mass and observe for dimpling; test mobility with the arm relaxed at the side and again when the patient presses the hand on the hip.
• Subareolar cords: tender cords may indicate mammary duct ectasia, a benign but sometimes painful condition with dilated ducts and inflammation and sometimes associated masses. Check for cysts and inflamed areas; some cancers may be tender. Distinguish hard, irregular, poorly circumscribed nodules that are fixed to skin or underlying tissue from mobile masses; a fixed mass when the arm is relaxed suggests rib and intercostal muscle attachment, while fixation when the hand is on the hip suggests attachment to the pectoral fascia. Inspect each nipple for elasticity; if nipple discharge is reported, determine origin by compressing the areola with the index finger in a radial pattern around the nipple to express discharge from any duct openings. Note the discharge color, consistency, quantity, and exact duct site. Thickening of the nipple and loss of elasticity can indicate cancer. Nonpuerperal galactorrhea includes milky discharge unrelated to pregnancy or lactation, often due to hyperprolactinemia, hyperthyroidism, pituitary prolactinoma, or dopamine antagonists (e.g., psychotropics, phenothiazines).

Nipple discharge can be spontaneous, unilateral, or multi-ductal; spontaneous bloody discharge warrants evaluation for intraductal papilloma, ductal carcinoma in situ, or Paget disease.

Axillae Exam

The axilla is typically examined in the sitting position. Inspect the axilla skin for rash, irritation, infection, or unusual pigmentation; unilateral, hyperpigmented axillary skin can indicate acanthosis nigricans associated with diabetes, obesity, polycystic ovary syndrome, or rarely malignant paraneoplastic conditions. In palpating the axilla, start with the left axilla (patient’s left arm down) using the right hand to reach toward the apex; palpate the central nodes first against the chest wall as they are most likely to be palpable. In the right axilla, use the left hand. Nodes that are large (≥ $1 ext{ cm}$ to $2 ext{ cm}$), firm, or hard, matted, or fixed to the skin or underlying tissues raise concern for malignancy. If central nodes are enlarged, palpate the other groups: anterior (pectoral) nodes along the anterior axillary fold inner border of the pectoralis major; lateral (humeral or deep) nodes along the upper humerus; posterior (subscapular) nodes in the posterior axillary fold; infraclavicular (deltopectoral) and supraclavicular nodes. The central nodes are often the first palpable group, and enlarged axillary nodes may result from hand or arm infections, recent immunizations or skin tests, or generalized lymphadenopathy.

Special Techniques

Examination after mastectomy or breast reconstruction requires attention to scarring and lymphedema risk due to interrupted drainage. Inspect the scar and axilla for masses, nodularity, or inflammation; palpate along the scar and near reconstruction areas with a circular motion using two or three fingers. Pay special attention to the upper outer quadrant and axilla. Recording of findings is flexible: initial notes may be sentences; later notes use concise phrases.

Recording Your Findings

Examples include:

• "Breasts symmetric and smooth without nodules or masses. Nipples without discharge."
• Or, for a concerning finding: "Breasts pendulous with diffuse fibrocystic changes. Single firm 1 × 1 cm mass, mobile, nontender, with overlying peau d’orange in the right breast, upper outer quadrant at 11 o’clock, 2 cm from the nipple." Such findings may suggest breast cancer and warrant further evaluation.

Health Promotion and Counseling: Evidence and Recommendations

This section covers breast cancer epidemiology, risk assessment, prevention, screening, and decision-making tools.

• Breast cancer is the most commonly diagnosed cancer worldwide and the leading cause of cancer death among women. In 2015, about
  $2.4 ext{ million}$ women were diagnosed globally and more than
  $0.5 ext{ million}$ deaths occurred. In the United States, breast cancer is the most commonly diagnosed cancer among women and the second leading cause of cancer death after lung cancer. A female born today in the U.S. has about a
  12 ext{%} ($0.12$) lifetime risk of developing invasive breast cancer and a
  2.6 ext{%} ($0.026$) lifetime risk of dying from breast cancer. About 80 ext{%} of new diagnoses occur after age $50$, with a median age of diagnosis around $62$. The probability of being diagnosed increases with age (see Box 18-1). Mortality rates have declined since the early 1990s. Box 18-1 presents probabilities by age interval; lifetime risk is approximately 12.4 ext{%} (1 in 8).

• Risk factors include increasing age, first-degree relatives with breast cancer (especially two or more relative diagnoses at an early age), inherited genetic mutations, personal history of breast cancer or ductal/lobular carcinoma in situ, biopsy-confirmed precancerous lesions, dense breast tissue on mammography, prior high-dose chest radiation at a young age, and high endogenous hormone levels. The National Cancer Institute’s Breast Cancer Risk Assessment Tool (the Gail model) incorporates age, race/ethnicity, personal history, chest radiation, genetic mutations, first-degree relatives with breast cancer, biopsy results, age at menarche, and age at first birth to estimate risk. Useful tools include:

• Gail model: $http://www.cancer.gov/bcrisktool/$

• Know BRCA Tool: $https://www.knowbrca.org/$

• Prevention: Healthy behaviors (physical activity; fruits/vegetables; limiting alcohol) may reduce risk. The USPSTF gives a Grade B recommendation for using a risk tool to screen for BRCA mutations among women with a family history of breast/ovarian/tubal/peritoneal cancers. BRCA mutations account for up to 10 ext{%} of all breast cancers. Women with a positive screen may be referred for genetic counseling and BRCA testing. High-risk women may consider intensified screening and preventive options:

• Bilateral mastectomy puede reduce incidence and mortality by between 80 ext{%} and 100 ext{%}.

• Selective estrogen receptor modulators (SERMs) like tamoxifen and raloxifene can reduce risk but increase thromboembolic and endometrial cancer risks. Aromatase inhibitors also show preventive efficacy in high-risk postmenopausal women, though FDA approval for this indication is not universal. The USPSTF recommends chemoprevention for high-risk women who are also at low risk for medication complications (Grade B).

• Drug uptake for chemoprevention remains low in practice.

Screening and Guidelines

Screening recommendations vary by age and risk. Mammography is the primary screening tool. For average-risk women, the USPSTF recommendations include:

• Biennial mammography for women aged $50–74$ (Grade B).
• Individualized decision-making for women aged $40–49$ (Grade C).
• Insufficient evidence for women aged $75+$ (Grade I).
• Evidence on newer modalities like digital breast tomosynthesis (DBT) is inconclusive for screening; use adjuncts (ultrasound, MRI) in dense breasts only with clinical indication. Box 18-3 summarizes benefits and harms by age.

Guidelines from other organizations include:

• American Cancer Society (ACS): screening starting at age $40–45$ (optional annually up to age $45–54$; then $55+$ biennial with annual continuation possible).

• American College of Obstetricians and Gynecologists (ACOG): screening starting at age $40$; frequency every 1–2 years; continue at least until age $75$.

• The boxes also note that evidence guiding screening for higher-risk women is limited; high-risk individuals may begin earlier, consider annual screening with DBT and MRI, and discuss risk-reducing strategies.

• A significant point: the prevalence of chemoprevention use among eligible women is low, and there are ongoing debates about benefits vs. side effects. DBT and MRI may be considered for high-risk individuals, especially those with dense breasts or genetic risk.

Breast Cancer in Men

Male breast cancer accounts for less than 1 ext{%} of breast cancer cases in the United States. In 2018, around $2{,}550$ new cases were expected with approximately $480$ deaths. Men often present at an advanced stage due to low suspicion and limited screening. Risk factors include older age, prior radiation exposure, BRCA mutations, Klinefelter syndrome, testicular disorders, alcohol, liver disease, diabetes, and obesity.

Common Breast Masses and Signs

The three most common masses are fibroadenoma (benign), cysts, and breast cancer. Fibroadenoma typically occurs in the age range of $15–25$ years (puberty to young adulthood), though it can present up to age $55$. Features:

• Usually single, may be multiple; shape is round, disc-like, or lobular; size often $1–2 ext{ cm}$; usually mobile; usually nontender; retraction signs are absent.

Visible signs of breast cancer include:

• Retraction signs due to fibrosis; nipple inversion or deviation; skin dimpling; edema with peau d’orange; abnormal contour; and Paget disease presenting as dermatitis of the nipple/areola with underlying ductal carcinoma. The incidence and signs can be summarized as in Tables 18-1 and 18-2 (Common Breast Masses; Visible Signs of Breast Cancer).

Spontaneous unilateral bloody nipple discharge warrants evaluation for intraductal papilloma, ductal carcinoma in situ, or Paget disease; nonbloody discharges that are multi-ductal are usually benign. Other discharges require assessment for causes such as hyperprolactinemia.

Nipple and Areola Pathophysiology

The nipple’s elasticity and discharge characteristics are important in evaluation. Nipple discharge is more concerning when it is bloody or serous, unilateral, spontaneous, associated with a mass, and occurs in women ≥ $40$ years. True galactorrhea is discharge unrelated to pregnancy or lactation and is often due to hyperprolactinemia.

Recording Your Findings (Sample Phrases)

• Breasts symmetric and smooth without nodules or masses. Nipples without discharge.
• Breasts pendulous with diffuse fibrocystic changes. A single 1 × 1 cm mass, mobile, nontender, with peau d’orange in the right upper outer quadrant, 2 cm from the nipple.

References and Evidence

The material references various sources on anatomy, breast cancer risk, imaging, and screening guidelines (e.g., Gail model, BRCA testing, DBT, MRI, tomosynthesis). It also cites multiple professional organizations (USPSTF, ACS, ACOG) and emphasizes evidence-based screening and prevention strategies, while noting the variability and limitations of evidence in certain subpopulations (high-risk women, dense breasts, etc.).

Summary of Key Numerical and Conceptual Points

• Anatomy: 15$-$20 lobes; 20$-$40 lobules per lobe; two fascial layers; Cooper ligaments; Montgomery glands; areolar architecture.
• Quadrants and Tail: four quadrants plus tail of Spence; localization by clock-face or quadrant; typical mapping of disease.
• Lymphatics: about $3/4$ drainage to axillary nodes; six nodal groups; Rotter’s space; central nodes most often palpable.
• Physiology: nodularity is common; premenstrual changes; postmenopausal atrophy; nipple smooth muscle controls milk ejection; nipple reflexes should not be misinterpreted as disease.
• Male breast: rudimentary tissue; gynecomastia vs. pseudogynecomastia; cancer suspicion with hard irregular masses.
• History and Symptoms: lumps, pain, nipple discharge; cyclic variation; diagnosis guided by location, duration, and changes over time.
• Exam technique: best with a standardized up-and-down palpation pattern; four inspection views; arm positions reveal dimpling; supine palpation; documentation in descriptive phrases; mastectomy/reconstruction requires scar and lymphedema considerations.
• Screening and Prevention: risk assessment tools (Gail model, BRCA risk tools); BRCA mutations account for up to 10 ext{%} of cancers; chemoprevention options (SERMs, aromatase inhibitors) with benefits and risks; bilateral mastectomy yields substantial risk reduction (between 80 ext{%} and 100 ext{%}); DBT and MRI in high-risk groups; screening guidelines vary by age and risk (USPSTF, ACS, ACOG).
• Common Masses and Signs: fibroadenoma typical in 15$–$25; cysts; cancer signs include retraction, skin changes, nipple changes, and Paget disease; bloody discharge requires urgent evaluation.

These notes consolidate the major and minor points from the transcript into a cohesive study aid suitable for exam preparation. They cover anatomical structures, physiological processes, physical examination techniques, common pathologies, and evidence-based prevention and screening guidelines, with explicit numerical data where applicable.