Understanding breast cysts

St George's Hospital,
Published February 27th, 2012  |  Last updated June 17th, 2014

Lumps in the breast caused by cysts are benignNot dangerous, usually applied to a tumour that is not malignant. and relatively common. This article discusses the symptoms, diagnosisThe process of determining which condition a patient may have. and treatment of breast cysts.


What are breast cysts?

Breast cysts are fluid-filled sacs and they are a relatively common cause of breast lump. Approximately 7% of all women will encounter a palpable cyst during their lifetime. Although these lumps are non-proliferativeTypically related to cancers; a cancer or other condition that does not spread., they can vary considerably in size and result in much anxiety. Their presence can also affect the interpretation of clinical examination findings and mammograms. Cysts can be single or multiple, affect one breast or both breasts and change in response to hormonal fluctuations during the menstrual cycleThe monthly sequence by which a woman’s body prepares for potential fertilisation of an egg released from the ovaries, involving thickening of the uterus lining and then shedding of the lining when pregnancy does not occur..

What are the symptoms of breast cysts?

Ultrasound of a breast cyst

Most patients are alerted to a breast cyst by the appearance of a lump, however, tension within a cyst can be associated with significant pain. Following diagnostic confirmation with ultrasound scanning (Figure 1), symptomatic cysts can be treated with fine needle aspirationThe withdrawal of fluid or cells from the body by suction.. The aspirated fluid is not routinely sent for further evaluation, unless it is bloodA fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. stained or the cyst contains a solid component in which case it will not disappear after needle aspiration. The solid component of such cysts should be also subjected to ultrasoundA diagnostic method in which very high frequency sound waves are passed into the body and the reflective echoes analysed to build a picture of the internal organs – or of the foetus in the uterus. guided core biopsyThe removal of a small sample of cells or tissue so that it may be examined under a microscope. The term may also refer to the tissue sample itself. in order to exclude rare cancerousMalignant, a tumour that may invade surrounding tissues or spread to distant parts of the body. cystic lesions.

Treatment for breast cysts

Small cysts do not usually require treatment. Cysts that are large or painful can be easily treated using a needle and syringe to remove the cyst fluid. Any lump that remains after this should be investigated with a biopsy and mammographyA diagnostic and screening test using low-dose X-rays to detect breast tumours. The fluid obtained from the cyst is usually discarded, unless it is blood-stained or there is a residual lump. Blood-stained fluid can sometimes be associated with breast cancerAbnormal, uncontrolled cell division resulting in a malignant tumour that may invade surrounding tissues or spread to distant parts of the body., especially if there is a residual lump. In such cases it will be sent for further tests.

Following the needle aspiration of a symptomatic simple cyst, the vast majority of patients can be reassured and discharged, with warning that recurrence is a possibility. Simple cysts do not become cancerous. A small proportion of women diagnosed with gross cystic breast disease (GCBD) have been suggested to be at increased risk of breast cancer, however, the evidence remains insufficient to warrant closer surveillance.

Although the management of most cases can be successfully undertaken by the GP, patients should be referred to a breast specialist for baseline evaluation and the formulation of an agreed management plan.

Sources of further information


For further information on the author of this article, Consultant Breast Surgeon, Professor Kefah Mokbel, please click here.
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