BENIGN BREAST DISEASES

BREAST CYSTS

What are Breast Cysts?

Breast cysts are fluid-filled sacs. They are like small water balloons. At some time during their life around 7% of women present with a lump that they can feel.  Cysts are most common in the 40 – 50 year age group.  They often occur just prior to menopause and usually disappear at menopause.  

Hormone replacement therapy (HRT) and cysts

At present with increasing use of hormone replacement therapy it is not uncommon to see cysts in women aged more than 50.  Cysts which usually disappear at the menopause can continue to be present in women on HRT.  Cysts which disappeared at menopause prior to starting HRT can reappear after starting HRT. 

How do cysts form?

Breast change, a process called involution, starts sometime after the age of 30. During involution the breast background tissue (stromal tissue) is replaced by fatty tissue which makes the breast saggy and soft. The breast glandular tissue is replaced by fibrous tissue (fibrosis), small cysts (microcysts) and glandular tissue (adenosis). Normally one cannot feel the small cysts. Large cysts which you can feel (palpable cysts) are aberrations (deviations) of the normal process.  Cysts are outpouchings of milk ducts and have a lining. These lining cells secrete the fluid.  The fluid in a cyst may be clear or coloured (yellow, green, orange, blue or black). 

How do cysts present?

A large cyst can appear overnight. Some cysts remain the same size. Some shrink and disappear.  Cysts which have fluid under tension can be felt easily and can be painful even if they are small (tension cysts).  Sometimes large cysts may not be felt in the breast as they may lie flat and are soft like the rest of breast tissue (lazy cysts). Cysts are sometimes uncomfortable or painful.  Cysts get tender or enlarged in the days before the period. Pressing on cysts can make them tender.   

Which patients with breast lumps should be referred to the hospital?

URGENT REFERRALS

Women aged 30 years and older

With a discrete lump that persists after their next period, or presents after menopause

Women aged younger than 30 years

With a lump that enlarges

With a lump that is fixed and hard  

And who have other reasons for concern such as family history

NON URGENT REFERRALS

Women aged younger than 30 years with a lump.   

How are cysts diagnosed and what tests are done?

Cysts cannot be clearly distinguished from solid lumps by physical examination or by mammographic examination. Hence the recommended ideal and most accurate examination is ultrasonography with or without needle aspiration.  

 How are cysts managed?

If a cyst is large enough to feel, the clinician will usually offer to aspirate (drain) the fluid using a needle. Aspirating the fluid removes the lump and helps women to stop worrying. Cysts that can be seen on ultrasound, and are too small to feel do not usually need aspiration. 

To aspirate a cyst, a fine needle is used and the cyst fluid is aspirated to dryness.  This is best done under ultrasound control. Aspiration with a needle can be uncomfortable, but is not usually painful. Where ultrasound is not easily available aspiration can also be performed in the clinic once a diagnosis is established and the cyst is palpable. If you have a cyst drained and the lump refills within 24 hours, you should make an appointment to see the doctor again or speak to your breast care nurse.   

Fluid is not sent for testing unless it is bloodstained. If a lump is still felt, after aspiration further assessment is essential.  

The majority of cysts are simple cysts as seen under ultrasound.  It is not uncommon to see a cyst with some internal echoes (atypical or complex cysts) in approximately 5%–5.5% of all breast ultrasound examinations of which 0.3% can be cancerous. If the complex cyst has a mass within the cyst a biopsy of the mass is performed (see picture).   

Mammograms are done for patients over 35 years of age and if they have not had one within the past 12 months. 

Can cysts come back?

Many women have cysts that come back.  Recurring cysts are treated the same way as the first cyst.  If you feel a new lump and if it does not disappear after your next period or within 2 – 3 weeks make an appointment to see your doctor.   

For more information contact: sasi@mybreastcare.org

This information sheet is aimed at women who have been examined by a breast specialist and found to have a benign cyst (non cancerous) condition. It is not a substitute for the advice of a qualified doctor. It is intended to provide information for better understanding and reassurance