A breast cyst is an accumulation of fluid within the breast, often resulting in a breast lump that you can feel.
If you find any breast lump, whether you think it is a cyst or not, it is essential to consult your health care provider as soon as possible.
About 25% of breast cysts enlarge gradually into ‘big-enough’ cysts to become a palpable breast lump.
Breast cysts are extremely common, and occur in as many as one third of all women between the ages of 35 and 50.
Are Breast Cysts Cancer?
It is important to note that breast cysts are a benign lesion and do not progress to breast cancer and do not increase the risk of cancer.
Depending upon the features of the particular cyst, such as the amount of solid elements inside it, the cyst may have the remote chance that a malignant breast cancer somewhere in the background is the root cause.
However, The chances of an epidermoid cyst actually being related to malignant breast cancer are extremely low- not even a 1/2 % chance.
What is a cyst?
Here is an ultrasound picture of a cyst in the breast.
The black oval in the center of the cyst is actually fluid
A simple cyst has a smooth, thin wall around it with no solid matter in the middle, only fluid.
What causes a cyst?
Breast cyst walls usually occur in the terminal duct lobular unit (TDLU), or right where the lobules transfer the milk into the ducts. In terms of the mechanics of breast functioning, when things go amiss, they tend to go amiss in the TDLU.
It is possible that a cyst could be caused by swelling from inflammation at the TDLU.
Rarely, there might even be an underlying infection. However, infections tend to have other obvious clinical features such as pain, redness and discharge.
Although infection is not common with a cyst, it occurs slightly more often in pregnant and breast feeding women.
Breast cysts tend to affect slightly older or pre-menopausal women, aged between 35 and 55 years. The cause of breast cysts are variations in hormone levels as a woman approaches menopause.
The fluid in a breast cyst is not milk, but a clear yellow fluid. Indeed, this is the same fluid that composes most of the liquid matter of the body.
Do breasts cysts increase the risk of breast cancer?
As I say, a cyst is a benign build up of fluid. A cyst can not ‘cause’ cancer and can not ‘evolve’ into breast cancer.
A breast cyst is an after-effect, unrelated to any kind of genetic cell-growth or metaplastic cells, that we usually associate with breast cancer and risk of breast cancer.
So, when people talk about breast cancer risks and breast cysts, they are talking about the cyst as a diagnostic side effect really.
If a cyst is not simple and homogeneous, (a complex cyst) but seems to have various complications or complexities, then there is a risk that malignant breast cancer may be the cause of these complexities.
Breast cancer can impose biological and cellular changes in the functioning of the breast ducts.
How are breast cysts discovered?
A breast cyst will either be discovered clinically or by breast self-examination as a ‘movable nipple lump‘. At other times, a cyst may show up on a screening mammogram, but mostly they are seen on ultrasound scans.
A mammographic image of a breast cyst can not reliably distinguish between a solid mass and a breast cyst. Indeed breast cancer is much more likely with the presence of a solid mass. Often, doctors in both case scenarios will refer a mass for an ultrasound.
Sonograms (ultrasound scans) are very useful at distinguishing between solid and liquid elements and diagnosing a ‘simple breast cyst’.
A simple cyst of the breast has a uniform oval shape, with thin smooth walls and a homogeneous fluid filling.
A radiologist can, with the benefit of ultrasound, get a pretty clear picture of the benign nature of a breast cyst. If there are really curious features or evidence of solid particles or nodules, then a biopsy will likely be necessary, usually by fine-needle aspiration.
Are there different types of classes of breast cysts?
At various times, different researchers have tried to propose various classification systems for breast cysts.
These classifications, however, are not necessarily useful for pathologists and radiologists with a lot of experience. What specialists are looking for are any qualitative and dynamic aspects of the sebaceous cysts that differ from the norm.
So, the general course of action, after drainage of the cyst, is follow-up and observation.
A continuum of cystic abnormalities: Simple, Complicated and Complex.
A ‘simple breast cyst’ is one which is obviously full of fluid and has a very regular oval shape with thin, smooth walls. These are the most common and the most obviously benign breast cysts.
However, the make up of breast cysts, as well as ovarian cysts can become more ‘complicated‘ with other presenting features. A cyst usually appears alone, but sometime appears in small ‘clusters‘. (clustered microcysts.)
If a breast cyst shows ‘septations‘ (septa, partitions or a loublated cyst), and so appears to have two or more ‘sections’, this is another complication.
A cyst may also appear to have some ‘thicker’ sections of the walls or small ‘nodular’ build ups, especially along the walls of the septations.
Simple breast cysts, epidermal inclusion cysts, and cysts with septa or appearing in clusters, are virtually always benign.
So, stop worrying, the likely recommendation will be for annual follow up only.
Complicated breast cysts usually need draining
A specialist will refer to breast cysts as ‘complicated’ when there are thicker sections of the walls.
However, these cysts are mostly, but not always, benign. A ‘complicated’ cyst will probably need drainage with fine needle aspiration under local anesthetic.
After drainage of the cyst, short term follow-up will be necessary.
A ‘complex breast cyst’ has a mixture of fluid and solid elements
If a breast cyst does not appear to be uniformly fluid-filled, but has some solid elements, this changes the picture considerably.
Cysts with a combination of fluid and suspended solid elements are usually called ‘complex‘ cysts. In addition, if the solid elements are really prominent doctors may name the cysts as a ‘complex cystic mass’.
Complex cysts will be taken more seriously by the physician and a biopsy will most likely be necessary. About 5% of breast cysts take on this ‘complex’ presentation.
Breast cysts should have uniformly thin walls
A simple rule regarding the imaging diagnostics of a breast cyst is that it should have a uniformly thin smooth wall.
If this uniformity is not present, then you have to worry about the part that is not thin and smooth and whether to insert a needle to drain it, or just follow-it-up.
It is a ‘subjective-continuum’ decision, not a black and white categorization with standard treatment processes.
Treatment for Breast cysts
Let me repeat that breast cancer is not likely in the following cases:-
- Big breast cysts that you can feel
- Cysts that hurt
- Simple ‘internal’ breast cysts that you are unaware of
These breast cysts tend to just be left alone with routine follow-up. If they are bothersome, drainage via needle aspiration may be necessary.
‘Complicated’ and ‘complex’ cysts will likely be drained regardless. Also, drainage with ultrasound guidance of the fine needle may be necessary for smaller, internal cysts.
The follow-up interval for a complex cyst will typically be a bit shorter, usually around 6 months.
Keep in mind that most of the women that have breast cancer, (whether it be ductal carcinoma in situ or an invasive breast cancer) are often in breast cancer support groups, so they can communicate and support other women who also have breast cancer.
Let’s add some Questions and Answers
Why do I get pain before a menstrual period from my breast cyst?
People only make guesses, nobody knows for sure, but it is common
Why do breast cysts need to be removed?
Two main reasons:-
- When a woman says “I want it removed, dammit, because it hurts, and it keeps coming back after cyst aspiration“
- If there is abnormal biopsy results surgical removal of the shift will be necessary.
When are breast cysts dangerous?
When a young doctor, lacking experience, tries to aspirate the cyst with a needle whilst the woman is sitting in a chair, and she feels faint and hits her head on the ground. THAT actually happens.
So, drain cysts while lying down, in the hands of a calming radiologist who uses ultrasound to guide the needle into the cyst.
Why do breast cysts hurt?
Cysts occupy the space of other breast tissue. The cyst can push aside, stretch or compress this normal breast tissue. So, the nerve endings for pain sensation start sending complaining signals to the brain about it.
Another reason for painful breast cysts is because some people rub or palpate them too hard. You can make any body part hurt by touching it too much.
My cyst had some debris inside, what is it?
It’s A) nothing to worry about. B) it might be the remnants of some blood in the cyst from the past, or like the mucous inside of your cheek (not exactly, just an analogy).
Are cysts absolutely benign?
If you have read this far then you know that yes, usually cysts are simple fluid-filled sacs and are benign (non-cancerous) breast disorders. Indeed, other benign disorders include:-
Are there different types of cysts?
There are many different classifications of cysts – often they relate to where they are found in the body such as:-
- arachnoid cysts (brain and spinal cord),
- pilonidal cyst (buttocks)
- ganglion cyst (occurs in any joint or tendon sheath)
- vallecular cyst (between the back of the tongue and throat)
- pineal cysts (pineal gland – brain)
- bone cysts
- epidermal (epidermoid) cysts (skin),
- sebaceous cyst
Is adenoid cystic carcinoma (sometimes called cystic carcinoma) related to breast cancer?
No, this is a very rare type of breast cancer and the malignant cells here are very similar to adeno cells (adeno cells are related to glandular secretions). Simple breast cysts, on the other hand, are a benign breast disease.
- Bruzzi P, Dogliotti L, Naldoni C, Bucchi L, Costantini M, Cicognoani A. (et al). (1997) Cohort study of association of risk of breast cancer with cyst type in women with gross cystic disease of the breast. BMJ 1997;314:925 (29 March) http://www.bmj.com/content/314/7085/925
- Chandrasekharan S, Whitney R. (2004) Cysts: are they always benign? Breast Cancer Research 2004, (6(suppl 1):p44. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3300404/
- Chang YW, Kwon KH, Goo D, Choi DL, Lee HK, Yang, SB. (2007) Sonographic Differentiation of Benign and Malignant Cystic Lesions of the Breast. J Ultrasound Med 26:47-53 https://www.ncbi.nlm.nih.gov/pubmed/17182708
- Devitt JE, To R, Miller AB. (1992) Risk of breast cancer in women with breast cysts Canadian Medical Association Journal, Vol 147, Issue 1 45-49 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1336118/
- Manneloo F, Tonti G, Darbre P. (2009) Concentration of aluminium in breast cyst fluids collected from women affected by gross fibrocystic breast disease. J Appl Toxicol. 2009 Jan;29(1):1-6.
- Mizia-Stec K, Zych F, Widala E. (1997) Biochemical and Endocrinological analysis of breast cyst fluid Ginekol Pol. 1997; 68(9):432-9 https://www.semanticscholar.org/paper/Biochemical-and-endocrinological-analysis-of-brea-Mizia-Stec-Zych/19cd5c5aed7ae3096a6d69105a049fab38cadf61
- Stella F, Biagioni S, Stella C, Cerroni L, Troccoli R. (1984) Cytology of breast cysts. Quad Sclavo Diagn. 1984; 20(3):283-94 https://www.ncbi.nlm.nih.gov/pubmed/6531428