Makindo Medical Notes

🩺 Breast Cysts are benign, fluid-filled sacs within the breast tissue. They are common in premenopausal women (35–50 yrs), hormonally driven, and may mimic malignancy. Understanding their pathophysiology, clinical presentation, and safe management is crucial in primary care and surgical practice.

ℹ️ Definition & Epidemiology

• Breast cysts are benign epithelial-lined, fluid-filled sacs within the breast ducts or lobules.
• Common in women aged 35–50 years, especially perimenopausal, rare after menopause (unless on HRT).
• They represent a major proportion of benign breast lumps seen in breast clinics.
• Often multiple, bilateral, and may recur.

🧬 Pathophysiology

• Thought to arise from dilated terminal duct lobular units (TDLUs) under oestrogen and progesterone influence.
• Fibrocystic change is the commonest background pathology.
• Cysts contain either clear, straw-coloured fluid or occasionally thick, green/brown fluid (so-called “blue dome cysts”).
• Cyst walls are lined by flattened epithelium, sometimes with apocrine metaplasia.

👩‍⚕️ Clinical Presentation

• Symptoms:
  • Discrete, smooth, fluctuant lump 🫧
  • May be tender, often cyclical with menses
  • Sometimes rapid onset lump (alarming to patient)
  • Occasionally nipple discharge or mastalgia
• Exam findings:
  • Well-circumscribed, mobile, cystic lump
  • Often indistinguishable from fibroadenoma on palpation
  • Tenderness more suggestive of cyst than solid lesion

🔎 Investigations – “Triple Assessment” (Gold Standard in UK)

• Clinical examination – history & physical.
• Imaging:
  • Ultrasound: First-line in <40 yrs. Cysts appear anechoic with posterior acoustic enhancement.
  • Mammography: First-line in >40 yrs. Cysts appear as round, well-circumscribed, radio-lucent lesions.
• Needle aspiration: Diagnostic & therapeutic. Confirms cystic nature by withdrawing fluid.
• Cytology: If aspirate is blood-stained or atypical → send for cytology to exclude malignancy.

🩸 Aspiration Findings

• Clear/straw fluid + lump resolves: No further action needed.
• Bloody fluid or residual lump: Send for cytology + refer for further assessment (biopsy).
• Recurrent cyst: Consider excision if persistent in same location.

⚠️ Red Flags (require exclusion of cancer)

• Bloody or blood-stained aspirate
• Lump not resolving after aspiration
• Skin changes, nipple retraction, or peau d’orange
• Strong family history of breast/ovarian cancer (BRCA risk)

🧾 Differential Diagnosis

• Fibroadenoma (common in younger women)
• Phyllodes tumour (rare, but can mimic cyst)
• Breast abscess (especially in lactating women)
• Carcinoma with cystic change

💊 Management

• Simple cyst, asymptomatic: Reassure, no intervention required.
• Symptomatic cyst: Fine needle aspiration (FNA) – diagnostic + therapeutic.
• Complex cyst (septations/solid elements): Core biopsy to exclude malignancy.
• Recurrent/persistent cyst: Surgical excision if symptomatic or suspicious.

📈 Prognosis & Follow-up

• Simple cysts are benign with no increased cancer risk.
• Some studies suggest women with multiple/complex cysts may have a slightly increased breast cancer risk, but not clearly established.
• Recurrence common; most managed conservatively.

🧠 Clinical Pearls

• In UK practice, triple assessment is the gold standard for all new breast lumps.
• Always aspirate if the diagnosis is uncertain and lump is tense/tender.
• Bloody aspirates always warrant cytology and further investigation.
• Reassurance is often key – patients are very anxious about “cancer.”

📚 References

• NICE CKS – Breast Lump
• Oxford Handbook of Clinical Surgery (Breast section)
• Bailey & Love’s Short Practice of Surgery