BENIGN BREAST DISEASES

BREAST CYSTS

FOR GENERAL PRACTITIONERS

Breast Cysts

A cyst is a fluid filled sac.

Age distribution of cysts (Adapted from Breast carcinoma risk and detection. WB Saunders.1981)

Cysts are most common in the age group of 40 – 50 years.  Breast involution begins after the age of 30.  Breast stroma gets replaced by fat and changes in the breast glandular tissue include areas of fibrosis, microcysts and formation of glandular elements.  An aberration in the normal involution process results in cyst formation. 

What is the incidence of cysts?

Around 7% of women present with a palpable cyst at some time during their lifespan. 50% of these will only ever have one symptomatic cyst. Cysts tend to disappear after the menopause.  Cysts are common in women who take hormone replacement therapy.  

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

URGENT REFERRALS

Who are female, aged 30 years and older

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

Who are female, aged younger than 30 years

With a lump that enlarges

With a lump that is fixed and hard

In whom there are other reasons for concern such as family history

NON URGENT REFERRALS

Women aged younger than 30 years with a lump. 

What is the relationship between breast cysts as a presenting symptom and breast cancer?

The evidence from literature has shown a risk from 1.7 to 7.5 times that of normal population in patients who present with a palpable lump. A study by Dixon et al of 1374 women with palpable cysts showed a relative risk of 3.24 in women with a palpable cyst compared to the normal population. 

What is the natural history of cysts?

Most cysts develop rapidly and then stay the same size. A small number shrink or continue to grow. Larger cysts can be felt in the breast tissue.  They might be firm or soft.  Often women have more than one cyst at a time.

What happens at the breast centre?

When patients are referred with a lump history is taken, clinical and ultrasound examinations are performed. Mammogram is performed if patient is over age 35.  Ultrasound guided aspiration of the cyst is the standard of care and cysts are categorized as simple cysts and complex / complicated cysts.   

Management of simple cysts:

• Asymptomatic: no treatment

• Symptomatic: aspiration under ultrasound guidance.

• Aspirate sent for cytology if:

• Blood-stained (The fluid within a breast cyst can be of any colour from pale to dark brown and is normally either clear or turbid ) 
• Lump does not disappear completely:
• Suspicious features on ultrasound
• Lump recurs.

Simple cysts are characterised on ultrasound as anechoic (black) lesions with smooth well-defined borders and thin capsule. The transmission of ultrasound waves through fluid gives the appearance of enhancement (white) deep to the lesion.   

Complex (or complicated) cyst is a sonographic diagnosis that is seen in 5% of all breast ultrasound examinations and  is characterised by internal echoes.  The rate of malignancy reported for these cysts is 0.3%. If the cyst also includes an intracystic mass or nodule, it is regarded as suspicious for neoplasm and is managed as a solid lesion, i.e. ultrasound guided core biopsy and managed according to the results of the core biopsy. 

Follow up of cysts

After triple assessment and aspiration of symptomatic lump patients are reassured and information leaflets about cysts are given.  They are advised to contact GPs if lump refills or if new lump occurs.