Breast Cysts
- What are breast cysts?
- What is “fibrocystic disease”?
- Do cysts lead to cancer?
- Do cysts need to be aspirated (drained)?
- Does cyst fluid need to be analyzed in the laboratory?
- What will happen if a cyst is left alone?
- Services at California Pacific Medical Center
What are breast cysts?
Cysts are fluid filled sacs within the breast. These sacs form when normal milk producing glands enlarge. The cause of this enlargement is not definitely known but is very likely related to an imbalance between the normal production and absorption of fluid. Breast cysts may be solitary but are most commonly multiple and can vary in size from microscopic to larger than a ping pong ball.
Breast cysts are common, particularly in women age 40-60. Although larger cysts can sometimes be felt as “lumps”, many cysts are undetectable by physical examination.
Cysts are frequently seen as abnormal shadows on mammograms. When this occurs, breast ultrasound examination is usually performed. Breast ultrasound is the most sensitive and accurate method for the identification and diagnosis of breast cysts. With modern ultrasound equipment accuracy rate of 95% to 100% can be expected.
In a study of more than 2,000 women in New York City, ultrasound found cysts in 30% of pre-menopausal women, in 7% who were post-menopausal and in 20% of post-menopausal women who were taking hormone replacement. Only 8% of these cysts could be felt at physical examination but half were seen on mammograms.
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What is “fibrocystic disease”?
This is an unfortunate term which has achieved wide usage. It is frequently used to describe the “lumpy breast.” This is a common condition usually unassociated with cysts and affecting at least half of normal women who may have irregular feeling breast tissue, cyclical pain and tenderness. These represent variable responses of breast tissue to cyclical fluctuations in levels of normal female hormones and is best designated as a benign “condition” not a disease.
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Do cysts lead to cancer?
Virtually all breast cysts identified as “simple cysts” by ultrasound are benign and remain so. It is estimated that perhaps 1 in 1,000 cysts may harbor a tumor (not necessarily malignant). These can usually be identified by their ultrasound appearance. Women with cysts are not at greater risk for the development of cancer although this risk may be minimally elevated if there is a positive family history for breast cancer (mother, sister, daughter).
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Do cysts need to be aspirated (drained)?
When a breast lump is found your doctor may elect to put a needle into it. This is a simple and effective technique which serves a dual purpose. It confirms the nature of the lump as “cystic” or “solid” and extracts fluid from a cyst which frequently makes the lump disappear. If no fluid is obtained the lump is presumed not to be a cyst and whatever material is aspirated may be sent to the laboratory for analysis. When a cyst is discovered by ultrasound, aspiration is not generally recommended unless the cyst has some unusual features on the ultrasound image, or the cyst is associated with discomfort (physical or emotional) which can be relieved by aspiration. If the cyst appears to contain material other than fluid on the ultrasound image an aspiration procedure may be recommended. This is best performed using ultrasound guidance to ensure complete drainage of the cyst.
Ultrasound-Guided Breast Cyst Aspiration
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Does cyst fluid need to be analyzed in the laboratory?
Studies of breast cyst fluid from thousands of women have established that laboratory analysis of fluid is of value only if the appearance of the fluid suggests previous bleeding. Normal benign cyst fluid is usually yellow, green or gray and can be safely discarded.
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What will happen if a cyst is left alone?
Breast cysts frequently fluctuate in size. This is commonly seen on routine annual mammograms. They may resolve and entirely disappear between annual examinations. This was observed in more than half of women with cysts followed at a Breast Center in Los Angeles. As mammograms of women with breast cysts may look different each year ultrasound may be requested to ensure complete evaluation. For this reason, comprehensive rather than screening mammograms are suggested for our patients with "cystic breasts".
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See additional Breast Care and Women's Health
Services at California Pacific Medical Center
Breast Cancer Recovery Program
Breast Health Center
St. Luke's Campus Breast Health Center
Lady's Touch
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