What is Sebaceous Carcinoma?

Sebaceous carcinoma (SC) is a rare type of skin cancer. It only develops on skin that has sebaceous glands. These glands, which help keep our skin moist, are found throughout the body. They are most plentiful around the eyes.

About 75% of SCs develop on an eyelid. The face and neck also contain many sebaceous glands, and this is where most other SCs develop. SC also can develop on the torso, leg, arm, inside the mouth, in the ear, on the genitals, and even on top of the big toe.

What Causes Sebaceous Carcinoma?
Scientists believe that the sun plays a key role in causing SC. Having a weak immune system or receiving radiation treatments for a medical condition also seems to increase the risk of developing SC.

Who Gets Sebaceous Carcinoma?
Anyone can develop SC, but some people have a greater risk:

• Middle age or older. It is very rare for SC to develop before 30 years of age. Most people are 60 years of age or older, and the risk continues to increase with age.

• Weakened immune system. People who have a weakened immune system have a much greater risk. A weakened immune system may be caused by a medical condition or medication. Medical conditions that weaken the immune system include human immunodeficiency virus (HIV) and cancer. Medication taken after transplant surgery to prevent the body from rejecting the new organ and some medications used to treat psoriasis or arthritis also weaken the immune system.

• Received radiation treatments for a medical condition. People who received radiation treatments as a child have been diagnosed with this rare skin cancer in their 60s and 70s. SC also develops in children who receive radiation treatments for retinoblastoma, a cancer that develops in the eye.

• Muir-Torre syndrome (MTS). This is a rare medical condition. People get MTS from the genes that they inherit from their parents. MTS greatly increases the risk for developing several cancers. The risk is greatest for a type of colon cancer. Other cancers that a person with MTS has an increased risk of developing are SC, cancers of the uterus, stomach, ovaries, intestine, urinary tract, liver, and bile duct.
  
  SC is often the first sign that a person has MTS.

Signs and Symptoms of Sebaceous Carcinoma
SC often appears as a small, slowly growing, firm, deep-seated mass on the upper eyelid. SC is 2 to 3 times more common on the upper eyelid than on the lower eyelid. It tends to look like a sty and to be painless.

As the cancer progresses, the affected eye may look like a person has a case of pink eye. Left untreated, SC can cause the affected eyelid to turn inward or outward. The eyelashes may fall out, and the person’s eyesight may become distorted.

When SC develops elsewhere on the body, the skin cancer looks like a slowly growing mass that is pink to reddish yellow in color. The mass may bleed.

How is SC Diagnosed?
When a dermatologist suspects skin cancer, the dermatologist performs a biopsy. This procedure can be safely performed during an office visit. To perform a biopsy, the dermatologist will remove the suspicious lesion, or part of it, so that it can be examined under a microscope. This is the only way to know whether a patient has skin cancer.

If the biopsy confirms that the patient has SC, the dermatologist may also:

• Perform a full-body skin examination to check for other skin cancers and check the patient’s lymph nodes for swelling.

• Ask if the patient or anyone in the patient’s family has MTS.

• Request that the patient have a thorough eye exam from an ophthalmologist if the SC occurs on an eyelid.

• Write orders for additional medical tests. These tests may include a chest x-ray, blood tests, urinalysis, and colonoscopy. Women may get an order for a mammogram. The purpose of these tests is to check for other cancers that are common in people who have MTS.

• Refer the patient to a medical geneticist. A medical geneticist can provide information about genetic testing and cancer screenings that may be appropriate.

Treatment for Sebaceous Carcinoma
A dermatologist considers many factors before determining which treatment will be best for the patient. These factors include the patient’s age, health, and where the SC is located on the body. Treatment options for SC include:

• Mohs micrographic surgery (Mohs). Mohs allows the surgeon to remove one layer of skin at a time. Each layer that is removed is placed under a microscope so that the surgeon can look for cancer cells. This process continues until the surgeon no longer finds cancer cells. Mohs often can be performed in a dermatologist’s office while the patient remains awake.

• Excision. Mohs may not be appropriate for every patient. If a tumor is large, SC may be treated with a surgical procedure called “excision.” This involves surgically removing DFSP and a portion of normal-looking skin. This procedure may be performed in a dermatologist’s office. Sometimes it needs to be performed in an operating room.

• Lymph node dissection. If the cancer has spread to nearby lymph nodes, the lymph nodes may be surgically removed.

• Radiation. This treatment is usually only an option when a patient cannot have surgery. If the cancer has spread to other parts of the body, radiation may be part of the treatment plan. It can help kill cancer cells and ease discomfort.

Follow-up Essential
When detected early, survival rates are good for people who have SC. But SC can return or spread to other areas of the body, so follow-up is essential. The dermatologist will tell you how often you should return for check-ups. It is essential to keep all of these appointments.

More Information
Sebaceous Carcinoma: What Does It Look Like?

References:
Blake PW, Bradford PT, Devesa SS et al. “Cutaneous appendageal carcinoma incidence and survival patterns in the United States: a population-based study.” Archives of Dermatology. June 2010, 146: 625-32.

Martinelli PT, Cohen PR, Schulze KE et al. “Sebaceous Carcinoma.” In Nouri K. [editor]. Skin Cancer. United States. McGraw Hill Medical; 2008. p. 240-9.

Nelson BR, Hamlet KR, Gillard M et al. “Sebaceous carcinoma.” Journal of the American Academy of Dermatology. July 1995; 33: 1-15; quiz 6-8.

All content solely developed by the American Academy of Dermatology