Epidermoid cyst

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Epidermoid cyst
An inflamed epidermoid cyst
Synonyms	Epidermal cyst, epidermal inclusion cyst, infundibular cyst, keratin cyst
Pronounce	N/A
Specialty	N/A
Symptoms	Skin-colored, round, firm lumps; may become red and inflamed
Complications	Infection, inflammation, rupture
Onset	Any age, commonly in adults
Duration	Can persist indefinitely if untreated
Types	N/A
Causes	Blockage of hair follicles, trauma
Risks	Acne, skin injury
Diagnosis	Physical examination, histopathology
Differential diagnosis	Lipoma, sebaceous cyst, pilar cyst
Prevention	N/A
Treatment	Surgical excision, incision and drainage
Medication	Antibiotics for infection
Prognosis	N/A
Frequency	Common
Deaths	N/A

An epidermoid cyst is a common type of benign cyst that forms in the epidermis, the outermost layer of the skin. These cysts are typically filled with keratin, a protein that is a key component of skin, hair, and nails.

Characteristics

Epidermoid cysts are usually small, round, and firm to the touch. They can appear anywhere on the body but are most commonly found on the face, neck, and trunk. The cysts are generally slow-growing and painless, although they can become inflamed or infected, leading to redness and tenderness.

Pathophysiology

Epidermoid cysts form when epidermal cells multiply in a localized area rather than shedding normally. This can occur due to trauma, blocked hair follicles, or other factors that cause the epidermal cells to become trapped beneath the skin.

Diagnosis

Diagnosis of an epidermoid cyst is typically made through physical examination. In some cases, imaging studies such as CT scans may be used to confirm the diagnosis or to rule out other conditions.

CT scan showing an epidermoid cyst.

Treatment

Treatment is not always necessary for epidermoid cysts unless they become symptomatic. Options include:

• Observation: Monitoring the cyst for changes.
• Incision and drainage: For inflamed or infected cysts.
• Surgical excision: Complete removal of the cyst to prevent recurrence.

Surgical removal of an epidermoid cyst.

Epidemiology

Epidermoid cysts are one of the most common types of cutaneous cysts. They can occur in individuals of any age but are most prevalent in adults.

Relative incidence of cutaneous cysts.

Related Conditions

Epidermoid cysts are sometimes confused with other types of cysts, such as sebaceous cysts and pilar cysts. It is important to differentiate between these conditions for appropriate management.

Gallery

• 
  Epidermal cyst located on the ear.
• 
  Epidermoid cyst of the testicle.
• 
  Macro view of an epidermoid cyst.

See also

• Sebaceous cyst
• Pilar cyst
• Dermoid cyst