Sebaceous Cyst- What is it?

Image of a sebaceous cyst of forearm.

Sebaceous cysts are small lumps that arise within the skin on the face, upper back, and upper chest usually although they can appear anywhere. A sebaceous cyst can form when the opening to a sebaceous gland becomes blocked. The oily substance called sebum continues to be produced but cannot escape to the outer skin surface.

The cyst may remain small for years, or it may continue to get larger. Sebaceous cysts are not cancerous.

Signs and Symptoms:

These dome-shaped cysts can be pea-sized or grow to a few inches or larger. They grow very slowly, and they’re not painful. If one touch them, then one should be able to move them around. They often have a central small black dot, or punctum, through which sebum accumulates.

Sometimes, however, they can become inflamed, infected, or suddenly rupture, which can increase the risk of infection.

Whatever the cause, if one notice redness, tenderness, or warmth, that indicate that the cyst has become infected or there is rupture of the cyst and discharge of the contents one need to consult a doctor immediately.

Diagnosis:

Usually diagnosed clinically. Although sometimes radiological examination or FNAC may be required in some instances.

Treatment:

If the cyst is causing symptoms or giving rise to complications, then surgery is the only treatment.

Surgical excision of a sebaceous cyst is a simple procedure done usually under local anesthesia to completely remove the sac and its contents. It should be performed when inflammation is minimal.

An infected cyst may require oral antibiotics or other treatment before or after excision. If pus has already formed, then incision and drainage should be done along with avulsion of the cyst wall with proper antibiotics coverage.

Usually chances of recurrence of the cyst are very low if the cyst along with its sac is excised completely.

Image of an excised specimen of sebaceous cyst