A breast cyst is a fluid-filled sac inside the breast tissue. Most women between 35 and 55 develop at least one cyst. They are completely benign in over 99% of cases — but because a cyst can feel like a lump, and because anxiety about lumps is so high, every cyst deserves clear assessment and reassurance.
Types of breast cyst
**Simple cyst** — round, sharply outlined, completely fluid-filled, no internal echoes. 100% benign. No further action unless symptomatic. **Complicated cyst** — fluid with debris or echoes inside but no solid component. Almost always benign (>97%). Usually monitored with ultrasound at 6 months. **Complex cyst** — has both fluid and a solid wall component. Needs biopsy because malignancy risk rises to 10–30%.
Symptoms
Most cysts are silent and found incidentally. When symptomatic:
- •A smooth, mobile, often tender lump
- •Pain that builds before the period
- •A feeling of fullness or pressure
- •Sudden enlargement (rapid filling) — uncomfortable but not dangerous
How a cyst is diagnosed
Ultrasound is the single best test. A simple cyst on ultrasound needs no further imaging or biopsy. Mammogram alone cannot reliably distinguish a cyst from a solid lump — which is why women under 40 are usually scanned by ultrasound first.
When aspiration (drainage) is recommended
Aspiration is a quick outpatient procedure where the cyst fluid is drawn out with a fine needle under ultrasound guidance. Local anaesthetic is rarely needed. Indications:
- •Significant pain or pressure
- •Very large cyst (>3 cm) causing distortion
- •Complicated/complex cyst (sample sent for cytology)
- •Patient preference for confirmation
Clear fluid — no further action. Blood-stained fluid — sent for cytology and re-imaged. Residual mass after drainage — biopsy.
Will the cyst come back
Yes, often. Up to 30% of drained cysts refill within months. This is normal and does not mean anything serious. Repeat aspiration is reasonable. Surgical excision is rarely needed and only considered for recurrent symptomatic cysts.
When to see a surgeon
- •A new lump that is hard, fixed, or skin-tethered
- •Blood-stained nipple discharge
- •A complex cyst on ultrasound
- •Persistent pain affecting sleep or activity
- •Any uncertainty after a previous scan
Book a consultation with Dr Vanesha at Medcare Al Safa via Okadoc or WhatsApp +971 58 500 4596.