MAMMOGRAPHY

BREAST ANATOMY & MAMMOGRAPHIC CORRELATION

I. MALE vs FEMALE BREAST

(Always compare first — it clarifies everything.)

1. Male Breast

Anatomy

• Rudimentary (underdeveloped)

• Mostly:

  • Skin

  • Subcutaneous fat

  • Small ducts

• No lobules

Mammographic Appearance

• Appears radiolucent (dark) due to fat

• Thin, linear retroareolar density may be seen

• Gynecomastia → flame-shaped density behind nipple

📌 Key point:

2. Female Breast

Anatomy

• Fully developed

• Contains:

  • Lobes

  • Lobules

  • Ducts

  • Fat

  • Cooper’s ligaments

Mammographic Appearance

• Mixed:

  • Fat (dark)

  • Fibroglandular tissue (white)

• Density varies with age and hormonal status

📌 Key point:

II. DEVELOPMENTAL STAGES OF THE BREAST

2.1 Fetal Stage

Anatomy

• Breast development begins at ~6 weeks gestation

• Mammary ridges (milk lines) form

• No functional glandular tissue

Mammography

• ❌ Not applicable

📌 Foundation stage only

2.2 Puberty

Anatomy

• Estrogen stimulates:

  • Ductal growth

  • Lobule formation

• Fat and fibroglandular tissue increase

Mammographic Appearance

• Very dense breast

• Predominantly white (fibroglandular tissue)

⚠ High density → ↓ sensitivity of mammography

📌 Exam pearl:

2.3 Menstruation (Reproductive Years)

Anatomy

• Cyclic hormonal changes

• Breast becomes:

  • Engorged

  • Tender pre-menstruation

Mammographic Appearance

• Density fluctuates

• Slight increase in glandular prominence pre-menses

📌 Best timing:

2.4 Menopause

Anatomy

• Estrogen decreases

• Glandular tissue begins to regress

• Fat content increases

Mammographic Appearance

• Decreasing density

• Better visualization of masses and calcifications

📌 Key advantage:

2.5 Post-Menopause

Anatomy

• Glandular atrophy

• Predominantly fatty breast

Mammographic Appearance

• Mostly dark (fatty)

• High contrast images

• Lesions are easier to detect

⚠ Hormone Replacement Therapy (HRT) may increase density

III. DIVISIONS OF THE BREAST

(Critical for localization and reporting)

3.1 Breast Quadrants

The breast is divided into four quadrants:

1. Upper Outer Quadrant (UOQ)

   • Most common site of breast cancer

   • Contains axillary tail (Tail of Spence)

2. Upper Inner Quadrant (UIQ)

3. Lower Outer Quadrant (LOQ)

4. Lower Inner Quadrant (LIQ)

📌 Mammographic correlation:

3.2 Clockface Reference System

Used to precisely locate lesions.

• Nipple = center of the clock

• Each breast has its own clock orientation

Example:

• “Lesion at 2 o’clock position, 3 cm from the nipple, right breast”

📌 Why this matters:

• Standardized communication

• Surgical and biopsy planning

• Follow-up comparison

FINAL SUMMARY (OLD-TUTOR STYLE)

• Male breast → simple, fat-dominant

• Female breast → hormone-responsive, complex

• Density changes with age and hormones

• Mammography works best in fatty breasts

• Quadrants give general location

• Clockface gives exact location

IV. EXTERNAL ANATOMY OF THE BREAST

(What we see, palpate, and position)

1. Skin

• Thin, elastic covering

• Contains hair follicles, sweat glands, sebaceous glands

• Mammography: skin thickening may indicate inflammation or malignancy

2. Nipple

• Central projecting structure

• Contains openings of lactiferous ducts

• Normal: symmetric, slightly protruding

• Abnormal: retraction or inversion → suspicious finding

3. Areola

• Pigmented circular area surrounding nipple

• Contains Montgomery glands (lubrication during lactation)

📌 Clinical note:

I. INTERNAL ANATOMY OF THE BREAST

1.1 Fascial Layers

The breast lies between two fascial planes:

a. Superficial Fascia

• Envelops breast tissue

• Divides into:

  • Anterior layer (beneath skin)

  • Posterior layer (above pectoralis major)

b. Deep Fascia

• Covers pectoralis major muscle

📌 Importance:

1.2 Retromammary (Fat) Space

• Loose connective tissue between breast and pectoralis major

• Allows breast movement during positioning

Mammographic relevance

• Loss of retromammary fat plane → possible chest wall invasion

1.3 Breast Parenchymal Components

(This is where cancer lives — understand this well)

1.3.1 Fibrous Tissue

• Structural framework

• Provides shape and firmness

• Appears radiodense (white) on mammography

1.3.2 Glandular (Secretory) Tissue

Function: milk production

1.3.2.1 Glandular Lobes

• 15–20 lobes per breast

• Arranged radially around the nipple

• Each lobe drains into a lactiferous duct

1.3.2.1.1 Lobules

• Subdivisions of lobes

• Contain clusters of acini (milk-producing units)

1.3.2.1.2 Terminal Ductal Lobular Unit (TDLU)

🚨 MOST IMPORTANT STRUCTURE IN BREAST PATHOLOGY

• Composed of:

  • Terminal duct

  • Associated lobules

📌 Key fact (memorize):

Mammography

• Changes here appear as:

  • Masses

  • Architectural distortion

  • Microcalcifications

1.3.3 Adipose (Fatty) Tissue

• Surrounds glandular structures

• Increases with age and menopause

Mammography

• Appears radiolucent (dark)

• Improves lesion visibility

1.3.4 Connective & Support Stroma

1.3.4.1 Cooper’s Ligaments

• Fibrous bands extending:

  • From skin → deep fascia

• Maintain breast shape

📌 Pathologic sign:

1.3.4.2 Extralobular vs Intralobular Stroma

• Extralobular: dense, fibrous (more rigid)

• Intralobular: loose, hormone-sensitive

📌 Hormonal influence explains density changes during life stages.

1.3.5 Lymphatic Channels

Drainage pathway (VERY TESTED):

• Axillary lymph nodes (primary)

• Internal mammary nodes

• Supraclavicular nodes

📌 Clinical relevance:

1.3.6 Circulatory (Blood Supply) System

1.3.6.1 Arteries

• Internal mammary artery

• Lateral thoracic artery

• Thoracoacromial branches

1.3.6.2 Veins

• Parallel arterial drainage

• Drain into axillary and internal thoracic veins

1.4 Pectoral Muscles & Deep Relations

Superficial Layer

• Pectoralis Major

  • Landmark on MLO view

  • Should be visible down to nipple level

Deep Layer

• Pectoralis Minor

• Clavipectoral Fascia

• Deep Fascia

📌 Mammographic rule:

Neurovascular Supply (Internal Network)

• Intercostal nerves (T2–T6)

• Provides sensation to nipple-areola complex

• Vascular + neural invasion → advanced disease sign

Associated Muscles & Internal Relations

• Serratus anterior

• Intercostal muscles

• Ribs & pleura posteriorly

📌 Chest wall invasion → poor prognosis.

Functional Summary

• Breast = modified sweat gland

• Primary function: lactation

• Secondary importance: hormonal responsiveness

🧫 HISTOLOGY OF THE BREAST

(Microscopic anatomy — examiner-level, but calm and clear)

I. CELLULAR COMPONENTS (DEEPER VIEW)

1. Epithelial Cells

Location

• Line ducts and lobules

• Form the inner layer of the TDLU

Function

• Secretion (milk during lactation)

• Hormone responsive (estrogen, progesterone)

Pathologic relevance

• Origin of most breast carcinomas

• Abnormal proliferation → hyperplasia, DCIS, invasive carcinoma

📌 Exam pearl:

2. Myoepithelial Cells

Location

• Between epithelial cells and basement membrane

Function

• Contract to expel milk

• Structural barrier against invasion

Histologic importance

• Present in:

  • Normal breast

  • Benign lesions

  • DCIS

• Absent in invasive carcinoma

📌 High-yield fact:

3. Stromal Cells

Components

• Fibroblasts

• Collagen fibers

• Blood vessels

• Immune cells

Role

• Structural support

• Influences tumor growth and spread

📌 Clinical note:

4. Adipocytes (Fat Cells)

Function

• Padding and energy storage

• Hormonal conversion (androgens → estrogen)

Mammographic correlation

• Fat appears radiolucent (dark)

• Improves lesion detection

II. MICROSCOPIC ORGANIZATION OF THE BREAST

Terminal Ductal Lobular Unit (TDLU)

🚨 Centerpiece of breast pathology

• Smallest functional unit

• Most hormonally sensitive

• Site of:

  • DCIS

  • Lobular carcinoma

  • Fibrocystic change

📌 Exam line to remember:

BREAST PATHOLOGY

I. BREAST ANOMALIES

(Congenital or developmental — not disease, but can mimic disease)

1.1 Asymmetry

• One breast differs in size, shape, or density

• May be normal or pathologic

Mammographic note

• Long-standing asymmetry → usually benign

• New or developing asymmetry → investigate

📌 Exam pearl:

1.2 Inverted Nipples

• Can be congenital or acquired

Benign

• Long-standing

• Bilateral

Suspicious

• New-onset

• Unilateral

• Associated with mass

📌 Red flag:

1.3 Accessory Nipples (Polythelia)

• Occur along the milk line

• Common, benign

Mammography

• Usually incidental

• No treatment needed unless symptomatic

1.4 Accessory Breast Tissue (Polymastia)

• Commonly in axilla

• Hormone-responsive

Clinical relevance

• Can develop:

  • Fibroadenoma

  • Carcinoma

📌 Exam tip:

1.5 Other Anomalies

• Hypoplasia

• Aplasia

• Tubular breast

• Poland syndrome

II. CLINICAL BREAST CHANGES

(These bring patients to the clinic)

2.1 Lumps

• Most common complaint

Benign

• Mobile

• Smooth

• Well-defined

Malignant

• Hard

• Irregular

• Fixed

📌 Imaging correlation:

2.2 Thickening

• Diffuse tissue firmness

• May be hormonal or inflammatory

⚠ Persistent thickening → investigate

2.3 Swelling

• Unilateral swelling is suspicious

• May indicate:

  • Infection

  • Inflammatory carcinoma

2.4 Dimpling

• Skin pulled inward

Cause

• Tumor infiltration of Cooper’s ligaments

📌 Classic malignant sign

2.5 Skin Irritation

• Rash or scaling

• Especially nipple–areola complex

⚠ Think Paget’s disease if persistent.

2.6 Pain (Mastalgia)

• Common and usually benign

• Cyclic pain → hormonal

• Non-cyclic, focal pain → evaluate

📌 Pain alone is rarely cancer, but never ignore focal pain.

2.7 Nipple Discharge

• Physiologic

  • Bilateral

  • Multiple ducts

  • Milky or green

• Pathologic

  • Unilateral

  • Single duct

  • Bloody or serous

📌 Bloody discharge = cancer until proven otherwise

2.8 Nipple Retraction & Areolar Changes

• Retraction

• Eczema-like changes

• Loss of normal contour

⚠ Suggests underlying malignancy.

2.9 Edema

• “Peau d’orange” appearance

• Caused by lymphatic obstruction

📌 Highly suspicious for inflammatory carcinoma

2.10 Erythema

• Redness of skin

Differential

• Mastitis

• Inflammatory carcinoma

📌 Failure to respond to antibiotics = biopsy

III. IATROGENIC & POST-TREATMENT CHANGES

(Very common exam traps)

3.1 Breast Implants

• Silicone or saline

Mammography

• Implant-displaced (Eklund) views required

• Implants may obscure tissue

📌 Implants do NOT increase cancer risk

3.2 Breast Reduction (Reduction Mammoplasty)

• Surgical scarring

• Architectural distortion

• Fat necrosis

⚠ Can mimic malignancy on imaging.

3.3 Postsurgical Excision

• Lumpectomy sites

• Scar tissue

• Clips present

📌 Always correlate with surgical history.

3.4 Radiation Changes

• Skin thickening

• Increased density

• Fibrosis

Time-dependent

• Early: edema

• Late: fibrosis

3.5 Others

• Fat necrosis

• Hematoma

• Infection

• Trauma-related changes

📌 Fat necrosis often mimics cancer.

MASTER SUMMARY (OLD TUTOR’S VOICE)

• Not every abnormality is cancer

• But every change deserves respect

• Compare sides

• Compare with old films

• Know surgery and radiation history