Sebaceous cysts
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Atheromas are a colloquial term for benign skin cysts filled with keratin, the protein that builds the stratum corneum of the epidermis, hair, and nails. Most commonly, this name describes epidermal cysts and pilar cysts, which develop within the dermis and subcutaneous tissue. The term “sebaceous cyst” is imprecise because the contents of a typical atheroma consist mainly of keratin, desquamated epithelial cells, and lipids, rather than sebum alone. The lesion usually takes the form of a slowly growing, movable nodule. It can remain asymptomatic for many years; however, rupture of its wall sometimes leads to a severe inflammatory reaction, pain, and swelling. Diagnosis is primarily based on clinical examination, while definitive confirmation of the nature of the removed lesion is provided by histopathological examination.
Sebaceous cysts - what do they look like
A typical sebaceous cyst is a round or oval nodule located under the skin, covered by normal-colored epidermis. Its diameter can range from a few millimeters to several centimeters. The lesion usually grows slowly, has a firm or elastic consistency, and remains movable relative to deeper tissues.
The most important clinical features include:
- a smooth, dome-shaped surface;
- clear demarcation from surrounding tissue;
- a small opening in the central part, called an orifice or punctum;
- possible discharge of a whitish-yellow, thick keratinous mass;
- a characteristic odor of the contents, resulting from the presence of keratin and lipid breakdown products;
- gradual enlargement of the lesion.
Epidermoid cysts often occur on the face, neck, back, chest, behind the ears, and in the genital area. Pilar cysts, also called trichilemmal cysts, are located primarily on the scalp, are usually firmer, and less frequently have a visible central punctum.
Rupture of the cyst wall releases keratin into the dermis. The body treats it as foreign material, resulting in an inflammatory reaction with redness, warmth, tenderness, and rapid enlargement of the nodule. Purulent discharge, fever, worsening pain, or spreading erythema require medical consultation.
Rapid growth, ulceration, bleeding, firm attachment to underlying tissues, or an atypical location indicate the need for further diagnostic evaluation.
Sebaceous cysts - where do they come from
An epidermal cyst is a hollow structure lined with stratified squamous epithelium that retains the ability to produce keratin. This material gradually accumulates in the lumen of the cyst, causing it to enlarge. Most epidermal cysts develop sporadically.
The primary mechanisms of their development include:
- obstruction of the follicular orifice and the accumulation of keratin in its infundibular portion;
- damage to the follicular wall in the course of acne or chronic inflammation;
- implantation of epidermal cells deep into the skin as a result of trauma, surgical procedure, or puncture;
- keratinization disorders within the pilosebaceous unit;
- familial predisposition, particularly evident in the case of multiple trichilemmal cysts.
Trichilemmal cysts originate from the outer root sheath of the hair follicle. In some families, they occur multifocally and can be inherited in an autosomal dominant pattern, which means the predisposition may be passed on to subsequent generations.
Multiple, early-appearing epidermal cysts, especially in atypical locations, may occasionally accompany genetically determined syndromes, such as Gardner syndrome. In such cases, the physician also assesses family history and the presence of other symptoms.
The mere occurrence of an epidermal cyst does not indicate inadequate hygiene. Washing the skin removes impurities from its surface, but has no effect on the epithelial capsule located in the dermis.
Sebaceous cysts and milia
Epidermoid cysts and milia contain keratin, but differ in structure, size, depth, and treatment method. A milium is a very small, superficial keratin cyst located just beneath the epidermis. It is usually 1–2 mm in diameter and resembles a white or creamy-yellow papule.
Feature | Epidermoid cyst | |
|---|---|---|
Typical size | From a few millimeters to several centimeters | Usually 1–2 mm |
Location | Dermis or subcutaneous tissue | Superficial part of the skin |
Appearance | Skin-colored nodule, sometimes with a central punctum | Small, white or yellowish papule |
Most common location | Face, neck, trunk, scalp | Eyelids, cheeks, temples |
Contents | Large amount of keratin surrounded by a capsule | Small amount of compact keratin |
Typical removal method | Excision of the entire cyst along with the wall | Superficial incision and evacuation of contents |
Primary milia can develop spontaneously, whereas secondary milia sometimes appear after trauma, burns, chronic skin diseases, or procedures that disrupt the epidermis. An epidermoid cyst forms a larger, distinct structure with an epithelial wall, which is why merely emptying its contents promotes cyst refilling.
Differentiating between the two lesions can be particularly important in the eyelid area. Nodules in this region may also correspond to xanthelasmas, sebaceous gland lesions, chalazia, or other conditions requiring different management.
Sebaceous cysts - can they be squeezed
Squeezing an epidermoid cyst at home carries the risk of damaging its wall and forcing keratin into the surrounding tissues. Keratin has strong irritant properties, so its release can trigger a rapid, often sterile inflammation. A red and painful epidermoid cyst is colloquially considered infected, although some such cases result precisely from the body's reaction to a ruptured cyst.
Possible consequences of mechanical squeezing include:
- increased pain and swelling;
- rupture of the capsule deep within the skin;
- formation of an abscess or secondary bacterial infection;
- spread of inflammation to the surrounding tissues;
- more difficult subsequent enucleation of the lesion;
- increased risk of scarring;
- rapid recurrence, because the epithelial wall continues to produce keratin.
Self-puncturing also hinders the assessment of the lump's nature and creates an entry route for microorganisms. Safe management consists of leaving the lesion unmanipulated and scheduling a dermatological or surgical consultation.
Urgent evaluation is required for: rapidly increasing swelling, severe throbbing pain, fever, purulent discharge, widespread redness, and a location near the eye, nose, or other sensitive anatomical structures.
Sebaceous cysts - how to remove
Proper diagnosis is the foundation of management. A typical epidermoid cyst can usually be identified based on its appearance and palpation. Ultrasonography is used for large, deep, or diagnostically ambiguous nodules. Lesions with an atypical presentation may require excision and histopathological evaluation.
The most radical treatment method remains the complete surgical removal of the cyst along with its wall. The procedure is usually performed under local anesthesia. The surgeon makes a small incision, separates the capsule from the surrounding tissues, removes the lesion, and, if necessary, closes the wound with sutures. Maintaining the integrity of the wall facilitates complete enucleation and limits the risk of recurrence.
The techniques used include:
- classic elliptical excision;
- enucleation through a small incision;
- minimal excision technique;
- removal through an opening made with a punch tool in appropriately selected lesions.
Active inflammation makes it difficult to separate the fragile cyst wall. Therefore, the doctor may first apply treatment to reduce inflammation and perform the actual excision after the tissues have settled. An abscess sometimes requires incision and drainage. An antibiotic is used when there are clinical signs of bacterial infection or inflammation of the surrounding tissue.
Emptying the cyst brings pain relief and reduces its volume, but the remaining wall can refill with keratin. That is why the completeness of removal is more important for the durability of the result than the size of the incision itself.
Treatments for sebaceous cysts
At Ambasada Urody Clinic & Spa, the qualification of skin lesions may include a specialist consultation and, depending on the clinical presentation, a dermatoscopic examination. The appropriate choice of method depends on the depth, size, location, and inflammatory activity of the lesion, as well as the need to preserve material for histopathological examination.
In the clinic's offer, epidermoid cysts are primarily associated with:
- Plexr Plus – a plasma technology designed for the precise treatment of selected, small, and superficial skin lesions. Its use requires prior confirmation that the clinical presentation corresponds to a benign lesion and that the method will allow the entire cyst to be properly treated;
- dermatological consultation and skin lesion qualification – enables the differentiation of an epidermoid cyst from a lipoma, milium, abscess, pilar cyst, and nodules of other origins;
- dermatoscopy – supports the assessment of superficial features of the lesion and the skin overlying the nodule, although a deep-seated cyst is primarily diagnosed clinically or ultrasonographically;
- surgical removal of a larger or inflamed lesion after proper qualification – allows for the removal of its wall and obtaining material for histopathological examination.
CO₂ laser, electrocoagulation, and cryosurgery are used at the clinic to treat specific benign skin lesions. In the case of a typical, deeper-seated epidermoid cyst, the use of tissue-destructive methods is limited, as a permanent outcome requires the removal of the entire epithelial capsule. These procedures may only be considered following an individual assessment of the type and depth of the lesion.
The chosen method should combine three goals: diagnostic certainty, complete removal of the cyst, and the most favorable aesthetic outcome possible.
