---

Breast - Important Topics for INICET

---

1. BENIGN BREAST DISEASE

Fibroadenoma

• Most common breast tumor in young women (<30 years)
• Originates from the terminal duct lobular unit (TDLU)
• Giant fibroadenoma: >5 cm; juvenile fibroadenoma: in adolescent girls
• FNAC: "bare bipolar nuclei" + stromal and ductal fragments
• Complex fibroadenoma carries slightly elevated cancer risk

Phyllodes Tumor (Cystosarcoma Phyllodes)

• Fibroepithelial tumor; "leaf-like" projections histologically
• Classified as benign, borderline, malignant
• Malignant phyllodes: sarcomatous stroma (not adenocarcinoma)
• Spreads hematogenously (NOT via lymphatics) - key MCQ point
• Treatment: wide local excision with 1 cm margins (NOT simple lumpectomy)

Breast Abscess

• Lactational (Staph. aureus) - peripheral, treat with antibiotics + aspiration
• Non-lactational (periareolar): Zuska's disease, squamous metaplasia of ducts, associated with smoking, Bacteroides/anaerobes
• Treatment: aspiration preferred over incision for lactational abscess

Duct Ectasia / Periductal Mastitis

• Dilatation of major subareolar ducts
• Presents: nipple discharge (brown/green), nipple retraction (slit-like/transverse), subareolar mass
• Distinguished from cancer by: bilateral, slit-like retraction (vs cancer: unilateral, late, vertical retraction)

Fat Necrosis

• Post-trauma or post-radiation
• Can mimic carcinoma clinically and mammographically
• Biopsy shows foamy macrophages, calcification

Mondor's Disease

• Superficial thrombophlebitis of the thoracoepigastric vein
• Presents as cord-like tender thickening along lateral breast/chest wall
• Self-limiting; NSAIDs

---

2. NIPPLE DISCHARGE - High-Yield Classification

• Intraductal papilloma: most common cause of bloody nipple discharge; subareolar; treated by microdochectomy
• Differentiate: ductogram/galactography or ductoscopy

---

3. IN SITU CARCINOMA (DCIS vs LCIS) - Extremely High Yield

• Comedo-type DCIS: central necrosis, calcification, most aggressive
• Van Nuys Prognostic Index (VNPI): used to guide DCIS treatment
• Treatment of DCIS: lumpectomy + radiotherapy OR mastectomy (no axillary dissection needed unless invasive component)

---

4. INVASIVE BREAST CARCINOMA - Types & Features

Classification (Foote & Stewart)

1. Invasive Ductal Carcinoma - NST (No Special Type): 80% - worst prognosis among special types
2. Invasive Lobular Carcinoma: 10% - "Indian file" pattern; E-cadherin negative; bilateral, multicentric
3. Medullary Carcinoma: 4% - well-circumscribed, lymphocytic infiltrate, pushing border; paradoxically better prognosis despite high grade; BRCA1 associated
4. Mucinous (Colloid) Carcinoma: 2% - mucin lakes; best prognosis; elderly women
5. Tubular Carcinoma: 2% - well-differentiated tubules; excellent prognosis
6. Papillary Carcinoma: 2% - elderly; good prognosis
7. Inflammatory Breast Carcinoma: peau d'orange, diffuse erythema, NO discrete mass; dermal lymphatic invasion on biopsy; T4d; worst prognosis; neoadjuvant chemo first

Key MCQs on Prognosis (Best to Worst)

---

5. PAGET'S DISEASE OF THE NIPPLE

• Eczematous, crusty, weeping nipple lesion
• Paget cells: large, pale, vacuolated cells in the rete pegs of nipple epithelium
• Almost always associated with underlying DCIS or invasive carcinoma
• Immunostaining: Paget cells - CEA positive, CK7 positive; S-100 negative
• Differentiate from pagetoid melanoma: S-100 positive in melanoma
• Treatment: mastectomy if underlying invasive cancer; lumpectomy + nipple excision if DCIS only

---

6. RISK FACTORS & GENETICS

Hormonal (Increased Estrogen Exposure = Higher Risk)

• Early menarche (<12 yrs), late menopause (>55 yrs)
• Nulliparity, first pregnancy >35 yrs
• HRT use >10 years (RR 1.2)
• Obesity in postmenopausal women (adipose tissue converts androgens to estrogens)
• Protective: breastfeeding (>12 months), early full-term pregnancy, oophorectomy

Genetic / Hereditary

• BRCA1 (17q21): 50-85% lifetime risk of breast cancer; 40% ovarian cancer risk; associated with Triple Negative Breast Cancer (TNBC); medullary pattern
• BRCA2 (13q12.3): 50-60% lifetime risk; 20% ovarian cancer; also prostate, pancreatic, male breast cancer
• HBC accounts for 5-10%; FBC for 20-30% of all breast cancers
• Other syndromes: Li-Fraumeni (TP53), Cowden (PTEN), Peutz-Jeghers, Ataxia-telangiectasia (ATM)
• Male breast cancer: more often BRCA2 mutation

---

7. TNM STAGING & CLINICAL STAGING - High Yield

• Bone is most common site of distant metastasis
• Brain metastasis most common in HER2+ and TNBC

---

8. BREAST INVESTIGATIONS - Triple Assessment (MCQ favorite)

1. Clinical examination
2. Imaging: Mammography (>35 yrs), USG (< 35 yrs or dense breasts)
3. Tissue: FNAC or Core needle biopsy (CNB preferred - gives histology + receptor status)

• BIRADS classification: 0-6; BIRADS 4-5 needs biopsy; BIRADS 6 = known malignancy
• MRI breast: best for BRCA carriers, dense breasts, implants, post-treatment monitoring
• Galactography: for bloody nipple discharge evaluation

---

9. SURGICAL PROCEDURES - Must Know

Mastectomy Types

• Patey's MRM: removes pectoralis minor, preserves pectoralis major
• Auchincloss-Madden MRM: preserves both pectoralis muscles (most common MRM done today)

Breast-Conserving Surgery (BCS/Lumpectomy)

• Multicentric disease
• Diffuse microcalcifications
• Prior radiation to chest wall
• Large tumor:breast size ratio
• Inflammatory carcinoma
• Positive margins on re-excision
• Patient preference for mastectomy
• Pregnancy (relative)

Sentinel Lymph Node Biopsy (SLNB) - Extremely High Yield

• First lymph node draining the breast = sentinel node
• Identified by: Patent blue dye + Tc-99m labeled sulfur colloid/albumin (dual technique)
• Fluorescent dyes (ICG) also used
• If sentinel node negative = no further axillary dissection
• If sentinel node positive = axillary lymph node dissection (ALND) - though Z0011 trial changed practice for early disease
• Avoids morbidity of full ALND (lymphedema, nerve injury)

---

10. MOLECULAR SUBTYPES (Biologic Types) - High Yield

• HER2 (HER2/neu, c-erbB-2): gene on chromosome 17q; amplified in ~20-25% cases
• HER2 testing: IHC (0,1+,2+,3+); FISH for equivocal (2+) cases
• ER/PR positive: tamoxifen (premenopausal), aromatase inhibitors (postmenopausal)

---

11. INFLAMMATORY BREAST CANCER

• No discrete palpable mass
• Peau d'orange, breast erythema, warmth, diffuse induration
• Dermal lymphatic permeation on skin punch biopsy (pathognomonic)
• Staged as T4d regardless of size
• Treatment: Neoadjuvant chemotherapy FIRST, then surgery + radiation (NOT surgery first)
• Worst prognosis of all breast cancers

---

12. SPECIAL SITUATIONS

Male Breast Cancer

• <1% of all breast cancers
• More often BRCA2 mutation
• Usually ER-positive; IDC most common type
• Presents late (poor awareness)

Breast Cancer in Pregnancy

• Most common cancer in pregnancy (after cervical cancer)
• Mammography safe (shielded); MRI without contrast preferred
• Surgery is safe in all trimesters
• Chemotherapy safe after 1st trimester
• Trastuzumab and hormonal therapy contraindicated in pregnancy

---

13. RECURRENCE & PROGNOSIS

• Strongest prognostic factor: Axillary lymph node status (number of positive nodes)
• Other important prognostic factors: tumor size, grade, ER/PR/HER2 status, lymphovascular invasion
• Nottingham Grading System (Elston-Ellis): tubule formation + nuclear pleomorphism + mitotic rate; Grade 1-3
• Local recurrence: biopsy (receptor status may change), whole-body MRI or PET-CT, then systemic chemo + surgery
• Bone mets: bisphosphonates + palliative RT
• Visceral crisis (liver/lung mets): systemic chemotherapy

---

16. QUICK MCQ RECALL TABLE

---