Applied Anatomy of the Breast
Carcinoma of the Breast
Epidemiology
- Most common cancer in females; more frequent in postmenopausal women (due to lack of oestrogen — BD Chaurasia)
- Origin: Epithelial cells of the lactiferous ducts (ductal carcinoma)
- Most common site: Upper lateral quadrant — ~60% of cases
- Common age group: 40–60 years
Clinical Signs of Carcinoma Breast — with Anatomical Basis
| Clinical Sign | Anatomical Basis |
|---|---|
| Painless hard lump | Tumour mass in breast parenchyma |
| Breast becomes fixed and immobile | Cancer infiltrates through retromammary space into pectoral fascia and pectoralis major |
| Skin retraction / dimpling | Cancer infiltrates and shortens the suspensory ligaments of Cooper → pulls skin inward |
| Retraction of nipple | Cancer infiltrates and causes fibrosis of lactiferous ducts → ducts shorten → nipple pulled inward |
| Peau d’orange (skin like orange peel) | Obstruction of superficial lymphatics by cancer → lymphoedema of skin → skin pits at hair follicles (cannot be lifted → orange-peel appearance) |
| Bilateral breast involvement | Cross-communication of superficial lymphatics across midline |
Spread of Carcinoma Breast
1. Lymphatic Spread (Most Important)
- Lateral quadrant → anterior axillary nodes → central → apical → supraclavicular nodes
- Medial quadrant → internal mammary nodes → supraclavicular nodes
- Inferomedial → subperitoneal plexus → ovary → Krukenberg’s tumour (transcoelomic)
- Also: liver (via lymphatics to subdiaphragmatic plexus)
2. Haematogenous Spread
- Via posterior intercostal veins → vertebral venous plexus (of Batson) → vertebrae, spinal cord, brain → intracranial dural venous sinuses
- This is a valveless system allowing retrograde flow
3. Direct Spread
- Into pectoralis major → chest wall
- Into skin → ulceration
Mastectomy — Types
| Type | Structures Removed | Notes |
|---|---|---|
| Simple (Total) Mastectomy | Entire breast only (all quadrants including axillary tail) | Used for non-invasive/pre-invasive carcinoma |
| Modified Radical Mastectomy | Breast + axillary lymph nodes + pectoralis minor (pectoralis major preserved) | Most common current operation; preserves chest wall muscles |
| Classical Radical Mastectomy (Halsted’s) | Breast + axillary lymph nodes + both pectoralis major and minor | Rarely done today; disfiguring |
The retromammary space (loose areolar tissue between breast and pectoral fascia) is the surgical plane used in simple mastectomy.
Surgical Incisions — Radial Principle
- Breast abscesses and surgical incisions are made radially to avoid cutting across multiple lactiferous ducts
- Radial incisions follow the direction of the ducts (which are radially arranged)
- Circumferential/transverse incisions would cut many ducts simultaneously
Mammography
- Radiological (X-ray) imaging of the breast
- Detects tumour masses, microcalcifications
- Used for early detection and screening of breast cancer
- Most effective method of early diagnosis
Fine Needle Aspiration Cytology (FNAC)
- Safe and quick method for diagnosis of breast lesions
- A fine needle aspirates cells from the lump for cytological examination
- Can differentiate benign from malignant lesions rapidly
Breast Self-Examination (BSE)
Key steps:
- Inspect both breasts in front of mirror for nipple discharge, puckering, dimpling, change in contour
- Check for change in colour of skin
- Retraction of nipple (sign of cancer)
- Palpate all four quadrants with palm of hand for any lump
- Feel for lymph nodes in axilla
- Mammogram if indicated
Retracted nipple is a sign of tumour unless proven otherwise.
Gynaecomastia
- Development of breast tissue in males
- Mainly occurs at puberty; usually bilateral
- Cause: hormonal imbalance (oestrogen excess relative to androgens)
- Associated with Klinefelter’s syndrome (47,XXY)
- Also occurs in liver cirrhosis, oestrogen-secreting tumours, drugs (e.g., spironolactone, cimetidine, digoxin)
Other Applied Points
- Superficial lymphatics communicate across midline → unilateral cancer can become bilateral
- Cancer through subperitoneal plexus → liver, and by ‘drop’ into pelvis → secondaries
- Self-examination is the only method for very early detection (BD Chaurasia)
Viva Pearls — Applied
- Most common cancer in females = carcinoma breast
- Most common site = upper lateral quadrant (60%)
- Origin of breast cancer = epithelial cells of lactiferous ducts
- Peau d’orange = obstruction of superficial lymphatics
- Skin dimpling = infiltration of suspensory ligaments of Cooper
- Nipple retraction = infiltration and fibrosis of lactiferous ducts
- Breast fixed to chest wall = infiltration of retromammary space → pectoral fascia → pectoralis major
- Krukenberg’s tumour = secondary ovarian tumour from inferomedial quadrant via subperitoneal plexus
- Brain metastasis route = posterior intercostal veins → vertebral venous plexus → brain
- Surgical incisions in breast = radial (to avoid cutting lactiferous ducts)
- Most common current operation = modified radical mastectomy