A sebaceous cyst is a term that loosely refers to either epidermoid cysts of pilar cysts. Because an epidermoid cyst originates in the epidermis and a pilar cyst originates from hair follicles, by definition, neither type of cyst is strictly a sebaceous cyst. The name is regarded as a misnomer as the fatty, white, semi-solid material in both of these cyst entities is not sebum, but keratin.
The scalp, ears, back, face, and upper arm, 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 in 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:
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.
With surgery, a cyst can usually be excised in its entirety. 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.
Blocked sebaceous glands, swollen hair follicles, and excessive testosterone production will cause such cysts.
Sebaceous cysts generally do not require medical treatment. However, it 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 complete remove the sac and its contents.
The typical outpatient surgical procedure for cyst removal is to numb the area around the cyst with local anesthetic, then to use a scalpel to open the lesion with either a single cut down the center of the swelling, or an oval cut on both sides of the centerpoint. If the cyst is mall, it may be lanced instead. The surgeon performing the surgery will squeeze out the keratin surrounding the cyst, then try to remove the cyst intact. If the cyst can be removed in one piece, the cure rate is 100%. If, however, it is fragmented and cannot be entirely recovered, the cyst may recur. An infected cyst may require oral antibiotics or other treatment before and/or after excision.