Summary

Benign Breast Disease encompasses a wide spectrum of non-malignant conditions, accounting for >90% of referrals to breast clinics. Most can be explained by the ANDI framework (Aberrations of Normal Development and Involution), reflecting hormonal changes throughout a woman's reproductive life. Common presentations include Fibroadenomas ("Breast Mouse" in young women), Cysts (Peri-menopausal), Cyclical Mastalgia (Pain), and Infection (Mastitis/Abscess). While benign, any breast lump MUST undergo Triple Assessment (Clinical + Imaging + Biopsy) to rigorously exclude malignancy. Management is largely conservative (reassurance), with targeted intervention for symptoms (e.g., draining cysts, antibiotics for mastitis).

Key Facts

• Most Common Lump <30: Fibroadenoma.
• Most Common Lump 30-50: Cyst.
• Most Common Symptom: Cyclical Mastalgia (Breast pain).
• Rule #1: Every lump is cancer until Triple Assessment says it isn't.
• Abscess: Lactational (Staph aureus) vs Non-Lactational (Associated with Smoking).
• Discharge: Milky/Green/Multi-duct = Benign. Bloody/Single-duct = Suspicious (Intraductal Papilloma vs DCIS).

Clinical Pearls

"The Breast Mouse": A Fibroadenoma is classically extremely mobile. You can flick it around the quadrant ("mouse"). Cancer is usually tethered/fixed.

"Halo Sign": On mammography, a cyst often has a lucent "halo" around it. Ultrasound confirms it is fluid-filled (anechoic) rather than solid.

"Smoking and Abscesses": Periductal Mastitis (recurrent subareolar abscesses) is strongly associated with smoking. Warning the patient: "If you don't stop smoking, this will keep coming back."

"Fat Necrosis mimics Cancer": After seatbelt injury or surgery, fat necrosis forms a hard, irregular, painless lump that may even cause skin dimpling. It feels EXACTLY like cancer. Biopsy is mandatory.

Aberrations of Normal Development and Involution (Hughes, Mansel, Webster). This theory posits that most benign "diseases" are actually minor exaggerations of normal physiology.

1. Fibroadenoma

• Pathology: Overgrowth of stromal and epithelial tissue.
• Demographics: 15-35 years.
• Features:
  • Highly mobile ("Mouse").
  • Firm, rubbery, smooth.
  • Painless.
• Management:
  • <3cm: Reassurance. (Can regress).
  • >3cm or Growing: Excision (Enucleation).
  • >5cm: Giant Fibroadenoma (Rule out Phylloides Tumour).

2. Breast Cyst

• Pathology: Dilated lobule filled with fluid during involution.
• Demographics: 35-55 years (Perimenopausal).
• Features:
  • Smooth, distinct lump.
  • Fluctuant (if large/superficial).
  • Can appear overnight (sudden).
  • Painful if tense.
• Management:
  • Aspiration: If symptomatic.
  • Fluid is clear/straw/green: Discard. Reassure.
  • Fluid is blood-stained: Send for Cytology (Risk of Intracystic Carcinoma).
  • Residual lump: Re-biopsy.

3. Mastitis and Abscess

• Lactational:
  • Breastfeeding women. Stasis of milk -> Infection (Staph aureus).
  • Systemically unwell (Fever/Rigors).
  • Tx: Continue breastfeeding (milk drainage is essential). Antibiotics (Flucloxacillin). Ultrasound-guided aspiration if abscess forms.
• Non-Lactational:
  • Periductal Mastitis: Occurs in smokers. Squamous metaplasia blocks ducts.
  • Recurrent subareolar abscesses / Mammary Duct Fistula.
  • Tx: Stop smoking. Antibiotics (Co-amoxiclav - needs anaerobic cover). Total Duct Excision if recurrent.

4. Duct Ectasia

• Pathology: Dilatation and shortening of major lactiferous ducts with age.
• Demographics: >50 years.
• Features:
  • Nipple retraction (slit-like).
  • Discharge (Creamy/Green/Cheesy).
  • Palpable subareolar mass.
• Tx: No specific treatment. Stop smoking.

5. Intraductal Papilloma

• Pathology: Benign warty growth within a duct.
• Presentation: Blood-stained nipple discharge from a single duct.
• Significance: Cannot distinguish from DCIS clinically. Requires Microdochectomy (removal of the duct) for histology.

6. Fat Necrosis

• Cause: Trauma (seatbelt, surgery).
• Presentation: Hard, irregular lump. Skin tethering.
• Assessment: Looks like cancer on Mammogram (spiculated) and Exam. Core Biopsy confirms "foamy macrophages" and necrosis.

          BREAST LUMP PRESENTATION
                     ↓
             TRIPLE ASSESSMENT
    (Exam + [US/Mammo] + Core Biopsy)
                     ↓
    ┌────────────────┴─────────────────┐
  MALIGNANT (B5)                 BENIGN (B2)
    (See Cancer)                       │
                                       ↓
                                WHAT IS IT?
                                       │
      ┌───────────────┬────────────────┼─────────────────┐
  FIBROADENOMA       CYST           ABSCESS          NODULARITY
      │               │                │                 │
  <3cm: Leave     Aspirate if      Us-Guided         Reassure
  >3cm: Excise    Symptomatic      Aspiration        (Cyclical)
                                   + Abx
                                   (Do NOT I&D
                                    unless necrotic)

1. Abscess Drainage

• Gold Standard: Ultrasound-Guided Aspiration (Needle).
  • Can be repeated every 2-3 days until resolved.
  • Less scarring, less fistula risk than open surgery.
• Incision and Drainage (I&D):
  • Reserved for skin necrosis or failure of aspiration.
  • Risk: If non-lactational, high risk of Mammary Duct Fistula (milk/pus leaking chronically).

2. Microdochectomy

• Indication: Single duct nipple discharge (Papilloma).
• Technique:
  • Lacrimal probe inserted into the discharging duct.
  • Circumareolar incision.
  • Duct isolated and excised.
  • Rest of ducts preserved (Breastfeeding still possible).

3. Total Duct Excision (Hadfield's Op)

• Indication: Multiple duct discharge, Duct Ectasia, Recurrent abscess.
• Technique: Removal of all major ducts behind the nipple.
• Result: Lose ability to breastfeed. Nipple sensation often reduced.

Cyclical Mastalgia

• Linked to menstrual cycle (Luteal phase). Heaviness/Tenderness.
• Management:
  • Reassurance: "It is not cancer". (The most effective treatment).
  • Support: Measured bra fitting. Sports bra.
  • Diet: Low fat, Evening Primrose Oil (Gamma-linolenic acid) - evidence weak but harmless.
  • Drugs: Topical NSAIDs. Tamoxifen (low dose) for severe refractory cases.

Non-Cyclical Mastalgia

• Chest wall pain (Tietze's / Costochondritis).
• Large pendulous breasts (Ligament strain).
• Infection.
• Cancer (rarely).

Key Guidelines

1. ABS (Association of Breast Surgery): Guidelines on management of breast pain and benign conditions.
2. NICE: Referral guidelines (2 week wait) for any discrete lump.

What is Benign Breast Disease?

It means "Not Cancer". The vast majority of breast lumps (9 out of 10) are benign. They are usually caused by normal hormonal changes, cysts (fluid sacs), or benign growths.

Do I still need tests?

Yes. We cannot tell for sure just by feeling. You will usually have a "Triple Assessment": Examination, Scan (Ultrasound or Mammogram), and a Needle Test (Biopsy). Once we prove it is benign, you can relax.

What is a Fibroadenoma?

It is a harmless overgrowth of tissue, often called a "breast mouse" because it moves around easily. It is common in young women. It does not turn into cancer. We usually leave it alone unless it gets very big.

What is a Cyst?

It is a fluid-filled bubble, like a blister, inside the breast. They are common before menopause. We can drain them with a needle in seconds, which stops the pain immediately.