| Sebaceous cyst | |
|---|---|
| Specialty | Skin  |
A sebaceous cyst (a form of trichilemmal cyst; also called: keratin cyst or wen; more correctly called: epidermal cyst or epidermoid cyst (see ICD-10 L72.0)) is a closed sac or cyst below the surface of the skin that has a lining that resembles the uppermost part (infundibulum) of a hair follicle and fills with a fatty white, semi-solid material called sebum. Sebum is produced by sebaceous glands of the epidermis.
The scalp, ears, back, face, and upper arms, are common sites for sebaceous cysts, though they may occur anywhere on the body except the palms of the hands and soles of the feet. In males a common place for them to develop is the scrotum and chest .They are more common in hairier areas, where in cases of long duration they could result in hair loss on the skin surface immediately above the cyst. They are smooth to the touch, vary in size, and are generally round in shape.
They are generally mobile masses that can consist of fibrous tissues and fluids, to a fatty, (keratinous), substance that resembles cottage cheese, or a somewhat viscous, serosanguinous fluid, (containing purulent and bloody material). The nature of the contents of a sebaceous cyst, and of its surrounding capsule, will be determined by whether the cyst has ever been infected. At surgery a cyst can usually be excised in its entirety; poor surgical technique or previous infection leading to scarring and tethering of the cyst to the surrounding tissue may lead to rupture during excision and removal. A completely removed cyst will not recur, though if the patient has a predisposition to cyst formation further cysts may develop in the same general area.
Causes
Blocked sebaceous glands, swollen hair follicles, excessive testosterone production, will cause such cysts.[1]
Treatment
Sebaceous cysts generally do not require medical treatment. However, if they continue to grow, they may become unsightly, painful, infected, or all of the above. Surgical excision of a sebaceous cyst is a simple procedure to completely remove the sac and its contents. An infected cyst may require oral antibiotics or other treatment before excision. Another common and effective method of treatment involves placement of a heat-pad directly on the cyst for about fifteen minutes per day, twice daily, for about 10 days (depending on size and location of the cyst). This method works by bringing the temperature of the wax-like material inside of the cyst to a temperature at which it melts and can be reabsorbed and processed by the body as a small amount of oily fluid. This method is preferred over surgery both for reasons of associated costs and risks of surgery. This methodology is not applicable for non-sebaceous cysts, however, as other varieties of cysts do not contain the same hardened sebum deposits, and therefor do not melt to be reabsorbed by the body.