Cysts

What is a cyst?

The term cyst is used to describe a variety of benign, dome-shaped growths that can be felt from the surface of the skin. A true cyst is enclosed by a sack-like wall. The most common type of cyst is referred to as an epidermoid cyst (aka epidermal inclusion cyst or sebaceous cyst). These cysts contain dead skin cells and release a thick, white substance with a foul odor when drained. You may have seen some of these drained on shows like Dr. Pimple Popper. Cysts that occur on the scalp are usually called pilar cysts and are similar to epidermoid cysts. 

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Cysts that are not contained within a sack are referred to as pseudocysts (a "false" cyst). These types of cysts are typically composed of dense, inflamed tissue, and if drained may express pus. An example of this type of cyst would be a large acne cyst. 

What causes cysts?

The cause of cysts is not entirely known. Epidermoid cysts may occur due to trauma or plugging of a hair follicle which prevents materials from properly draining to the surface of the skin. There is a strong genetic component as many patients report other family members having similar growths. Pseudocysts like an acne cyst are due to inadequately controlling the underlying condition. 

How is a cyst diagnosed?

The only way to truly diagnose a cyst is to perform a surgical removal of the growth and then send it for additional testing. A trained specialist such as a dermatologist can often diagnosis a cyst by examining the growth for features such as size, texture, assessing mobility of the growth, and taking a detailed personal and family history. When the physician is in doubt, additional testing including imaging or removal of the growth may be recommended. Symptoms that would cause concern that a growth may be cancerous would include rapid growth, pain, or having a growth that is immobile and "stuck" to other underlying structures. 

Do cysts need to be removed?

Unless a growth has concerning features as mentioned above, cutting it out is rarely required since most are benign, meaning they do not turn into cancer. Cysts can still be removed if they cause problems to the patient such as discomfort, become infected, or if the patient isn't happy with the cosmetic appearance of the growth. For some cysts, especially acne cysts, the growth can be injected with an anti-inflammatory steroid to reduce inflammation and shrink the growth. Sometimes this is sufficient and surgery is not required. 

How are cysts removed?

True cysts, such as epidermoid cysts, require surgical removal to fully get rid of the growth. If the cyst is simply drained, the sack remains and will fill up again. Popping them is not advised as it does not lead to permanent results and can lead to infection or severely painful inflammation. Surgical removal for most cysts can be done in-office under local anesthesia. For small cysts, a slit is made in the skin and they often "pop out" like you may have seen on social media. Many cysts require more work as the surgeon has to separate the cyst from the surrounding tissues that are attached. There is always a risk the cyst may return even with surgical removal so it is important to talk to your surgeon about the pros and cons of removal prior to deciding if surgical treatment is right for you.