Introduction:
A cyst is a pathological cavity filled with fluid, semifluid, or gaseous contents not created by the accumulation of pus. Most of the cysts are lined by epithelium, but not all are. Cysts lined by epithelium are known as “true cysts,” whereas cysts not lined by epithelium are known as “pseudocysts.” An epidermal inclusion cyst is a type of cutaneous cyst, and it is the most common of all types of cutaneous cysts.
The other names by which epidermal inclusion cysts are denoted are:
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Epidermoid cyst.
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Epidermal cyst.
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Infundibular cyst.
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Keratin cyst.
Epidermal inclusion cysts are sometimes referred to as sebaceous cysts; however, this is a misnomer as they do not involve any sebaceous gland. Epidermal inclusion cysts are mostly benign (non-cancerous). However, in a rare scenario, they may transform into malignancies. Malignant cases account for just about one percent of the cases.
What Does Epidermal Inclusion Cyst Look Like?
As it is a cutaneous cyst, an epidermal inclusion cyst is seen beneath the skin. Their characteristic appearance is dome-shaped lumps, which are slowly enlarging, painless, mobile, and fluctuant, often seen along with a punctum (a minute point from which surrounding tissues differ in color and appearance). Epidermal inclusion cyst deep inside the skin communicates with the outer skin through a keratin-filled orifice. Through this orifice, a malodorous yellowish cheese-like material is discharged. Their size may range from a few millimeters to centimeters. Its contents include degraded keratin and lipid materials.
Where Does Epidermal Inclusion Cyst Occur?
Epidermal inclusion cysts are the most common cutaneous cysts. They occur most commonly in the face, neck, scalp, back, chest, arms, legs, and genitalia and originate from the follicular infundibulum (upper portion of the follicle).
What Are the Epidermal Inclusion Cysts Filled With?
The epidermal inclusion cyst will be filled with keratin and cell debris. When these substances are draining, they look thick, yellow, and have a foul odor.
What Causes Epidermal Inclusion Cysts?
Epidermal inclusion cysts occur mostly randomly. They do not have any genetic linkage; however, certain genetic conditions are associated with the development of epidermoid inclusion cysts.
These include:
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Gardner syndrome (a type of familial adenomatous polyposis).
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Gorlin syndrome (an inherited disorder that affects many organs and tissues of the body).
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Favre-Racouchot syndrome (a disorder that consists of open and closed comedones in actinically damaged skin).
Chronically damaged skin due to sunlight exposure in old people is more likely to develop epidermal inclusion cysts, and certain medications are associated with this development.
That includes,
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BRAF inhibitors.
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Imiquimod.
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Cyclosporine.
Epidermoid inclusion cysts originate from the follicular infundibulum, and any disruption to the follicular infundibulum may result in cyst development. They can also occur due to the implantation of the epithelium into the skin below by any penetrating injury or trauma.
Who Is Most Commonly Affected by the Epidermal Inclusion Cyst?
They most commonly occur in the third and fourth decades of life. Male predilection is seen as compared to females (ratio 2:1). They are rarely seen before puberty.
What Are the Symptoms of Epidermal Inclusion Cyst?
The symptoms include a dome-shaped lump that is mobile, fluctuant, and painless. Sometimes, the lump may become painful as it gets infected and inflamed. The skin becomes red over the affected area. The condition is usually benign but may rarely transform into a malignant one.
How to Diagnose Epidermal Inclusion Cyst?
A simple clinical examination could provide a valuable diagnosis. In certain cases, your doctor might suggest other tests to rule out other findings.
These include,
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Punch Biopsy: The pathologist examines a small amount of tissue removed from the affected area. This helps rule out any cancer associated with the cysts and gives a definitive diagnosis of the condition.
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Ultrasound: Ultrasound helps determine the cystic contents. They appear as a round, oval-shaped, and well-circumscribed mass in the subcutaneous tissue.
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Computed Tomography (CT) Scan: A CT scan gives a detailed view of the cyst and helps the surgeon plan for treatment for cyst removal.
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MRI (Magnetic Resonance Imaging): MRI is very useful in delineating whether the cyst is benign or malignant.
How Is Epidermal Inclusion Cyst Treated?
In most cases, epidermal inclusion is left untreated as the condition is harmless and painless. The inflamed and uninfected cysts resolve spontaneously without treatment. However, closely monitoring the condition is necessary, as the cyst may rarely become painful and inflamed. It does not always transform into a malignant condition. Some of the different ways to treat the inflamed, painful conditions include:
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To reduce swelling, a doctor might suggest injecting a steroid medication into the affected area.
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Incision and drainage are done to drain out the yellowish, cheesy material discharging through the cyst via the skin orifice. Drainage of cysts avoids the chance of further infection in the affected area.
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Surgical excision helps remove the cyst completely. Your doctor will give local anesthesia to numb the affected area surrounding the cyst before the procedure.
What Are the Complications Seen in Epidermal Inclusion Cyst?
Some of the potential complications seen in epidermal inclusion cysts are,
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Inflammation: The cyst may appear swollen and tender even without cyst infection. Your doctor will suggest some anti-inflammatory medication before surgical removal of the cyst.
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Rupture of Cyst: Rupture of the cyst often leads to infection.
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Infection: An infection in the affected area leads to a severely painful condition. Doctors suggest antibiotics to treat the infection and subside the pain.
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Skin Cancer: Rarely, the epidermal inclusion cyst may transform into cancer. A cyst with such malignant potential requires complete removal to prevent its recurrence.
Is Epidermal Inclusion Cyst Contagious in Nature?
No, epidermal inclusion cysts are not contagious.
What Are the Risk Factors Related to Epidermoid Cysts?
Some common risk factors are
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The person is past puberty.
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If the person is affected by a rare inherited condition, such as Gardner syndrome,.
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Injury to the skin.
Is an Epidermoid Cyst a Sign of Cancer?
This condition is rarely harmful; some have seen these cysts become malignant.
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Squamous cell carcinoma.
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Basal cell carcinoma.
These cysts can be concerning if
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They show signs of infection, such as pain, swelling, and skin discoloration.
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Quick growth.
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Size is more than five centimeters.
Conclusion:
Epidermal inclusion cysts are the most common cutaneous cysts. They are mostly benign and rarely transform into malignant. Once infected, the cyst becomes painful. A doctor might suggest treatments like surgery, incision and drainage, and medication to treat the cyst. Although this condition occurs spontaneously, certain preventive measures, like avoiding trauma and injury to the skin and chronic sun exposure, could reduce the risk of developing the condition.
