From the Guidelines
Sebaceous cysts, also known as epidermoid cysts, are benign subcutaneous lesions that can be treated with observation, complete surgical excision, or incision and drainage, depending on their symptoms and complications, with antibiotics only necessary in cases of infection, as recommended by the Infectious Diseases Society of America 1.
Clinical Features
Sebaceous cysts are closed sac-like structures containing fluid, semi-solid material, or gas, lined by epithelium, and can be classified based on their origin as congenital, retention, exudation, traumatic, parasitic, neoplastic, or degenerative. They present as slow-growing, painless, round, firm, mobile swellings in the skin, commonly found on the face, scalp, neck, back, and genitalia, with a central punctum representing the blocked duct opening. These cysts contain cheesy, foul-smelling material composed of keratin and sebum.
Complications
Complications of sebaceous cysts include infection leading to abscess formation, rupture causing inflammation, calcification, horn formation, and rarely, malignant transformation into squamous cell carcinoma, especially in long-standing cases. Inflamed epidermoid cysts are typically not recommended for gram stain and culture of pus, as the inflammation and purulence occur as a reaction to rupture of the cyst wall and extrusion of its contents into the dermis, rather than as an infectious complication 1.
Treatment Options
Treatment options for sebaceous cysts include:
- Observation for asymptomatic cysts
- Complete surgical excision under local anesthesia, which is the definitive treatment
- Minimal incision technique where the cyst contents are expressed and the wall extracted
- Incision and drainage for infected cysts, followed by complete excision after the infection resolves, as recommended by the Infectious Diseases Society of America 1 Antibiotics are only necessary when infection is present, and the decision to administer antibiotics should be based on the presence or absence of systemic inflammatory response syndrome (SIRS) 1.
From the Research
Clinical Features of Sebaceous Cysts
- Sebaceous cysts, also known as epidermoid cysts (EC) or keratin cysts, are common benign tumors found on the scalp, ears, retroauricular areas, scrotum, face, and thorax 2
- They are subcutaneous nodules containing keratin and encapsulated by an epidermoid wall, mobile, smooth to the touch, variable in size, and most commonly located on the face, neck, and trunk 3
- They may rupture or become infected and inflamed, red, painful, or purulent 3
Complications of Sebaceous Cysts
- Infected sebaceous cysts can be a complication, which may require incision and drainage or other treatment methods 4
- Rupture or infection of the cyst can lead to inflammation, red, painful, or purulent conditions 3
- In rare cases, a sebaceous cyst can be a sign of an underlying malignant lesion, such as a metastasis of a sarcoma or carcinoma, which can be detected by the "granulated sweetener packet sign" 3
Treatment Options for Sebaceous Cysts
- Traditional surgical excision can completely eradicate the cyst, but may cause obvious scarring 5
- Minimally invasive surgery, such as CO2 laser punch-assisted surgery, can be a convenient and effective treatment option with minimal scarring and high patient satisfaction 5
- Intraoral approach for excising sebaceous cysts located in the lip or cheek near lip commissure can avoid a visible scar on the skin 6
- A minimal-incision technique can be a satisfactory alternative to conventional, more invasive surgery, with a low recurrence rate of 0.66% 2
- Suture closure after excision of infected tissue can be a simple and effective treatment method, with quick recovery and no need for frequent dressing 4