From the Guidelines
A sebaceous cyst is essentially the same as an epidermal cyst, though the term "sebaceous cyst" is technically outdated in medical terminology. These cysts are benign, slow-growing, firm lumps that develop beneath the skin when epidermal cells move deeper into the skin and multiply rather than sloughing off at the surface. They contain a cheese-like, foul-smelling substance made of keratin, not sebum as previously thought, which is why medical professionals now prefer the term "epidermal cyst" or "epidermoid cyst" 1.
Key Characteristics
- These cysts commonly appear on the face, neck, back, and genitals
- Typically don't require treatment unless they become infected, painful, or cosmetically bothersome
- If treatment is needed, complete surgical excision is the definitive approach to prevent recurrence, though minimal incision techniques or steroid injections may be used in some cases 1.
Important Considerations
- Despite the name confusion, these cysts are not related to the sebaceous glands and don't contain sebum
- The 2014 update by the Infectious Diseases Society of America recommends incision and drainage as the treatment for inflamed epidermoid cysts, carbuncles, abscesses, and large furuncles 1.
Treatment Approach
- Incision and drainage is the recommended treatment for inflamed epidermoid cysts
- Gram stain and culture of pus from inflamed epidermoid cysts are not recommended 1
- The decision to administer antibiotics directed against S. aureus as an adjunct to incision and drainage should be made based on the presence or absence of systemic inflammatory response syndrome (SIRS) 1.
From the Research
Definition and Characteristics
- Epidermoid cysts are benign cutaneous neoplasms resulting from the invagination and proliferation of epidermal cells within the dermal layer 2
- They are also known as epidermal cysts and can be found on the face, cervical region, upper torso, and scalp 2
- Sebaceous cysts are often referred to as epidermal cysts, particularly when found on hairy areas of the body such as the scalp, trunk, and face 3
Relationship between Sebaceous and Epidermoid Cysts
- Sebaceous cysts are considered a type of epidermoid cyst, as they share similar characteristics and origins 3, 4
- Both types of cysts can be treated with surgical excision, and the minimal excision technique is a less invasive option for epidermoid cyst removal 4
Clinical Presentation and Treatment
- Epidermoid cysts can present as firm, mobile nodules with a characteristic central punctum, and their clinical presentation can be variable 2, 5
- Surgical excision is the recommended treatment for sizeable or recurrent cysts, and complete removal of the cyst wall is necessary to avoid relapses 2, 5
- Malignant transformation is a rare but possible complication of epidermoid cysts, including sebaceous cysts 6