Sebaceous gland carcinoma is an aggressive but rare type of skin cancer. It is commonly found in the eyelid, but it can occur anywhere since sebaceous glands are found throughout the body. This type of cancer is often misdiagnosed as other, less serious afflictions.
Carcinoma is a type of malignant cancer that forms from epithelial cells. Since it is malignant, it can spread easily to surrounding tissues. Advanced stages of carcinoma may metastasize through the lymphatic or circulatory systems to dock in other organs or parts of the body.
Sebaceous glands are found in the dermis, or middle, layer of the skin. They secrete sebum, an oily substance that keeps skin and hair pliable. These glands can easily become clogged with dried sebum, dirt, or bacteria, and the blockages can form hard nodules that are usually painless, but which are visible on the surface of the skin.
Similarly, sebaceous gland carcinoma causes hard and painless nodules on the skin, but these nodes are actually malignant tumors. The inside of the eyelid is the most common place for the tumors to form because there are many sebaceous glands in that particular area. The tumors are raised and highly vascularized, meaning that they have many blood vessels. A biopsy may be necessary to correctly diagnosis this condition.
As tumors increase in size, they may become pigmented — the tumors usually become more yellow as they grow. This coloring is due to the addition of lipids as the tumor spreads from the dermal layer to the epidermis. The tissue around the tumor typically becomes red and inflamed.
Sebaceous gland carcinoma tumors can be removed with surgery, but more aggressive cancer treatments may also be necessary. Radiation or chemotherapy is recommended to patients, especially in advanced stages of the disease. There is a high mortality rate for this cancer due to the high rate of metastasis.
This disease is most common in older people and younger individuals with other eye abnormalities, like retinoblastoma. It is also more prevalent in women. This form of cancer is much more rare than the similar disease basal cell carcinoma.
Sebaceous gland tumors may also be a symptom of Muir-Torre syndrome. Patients with this syndrome present with several malignant cutaneous tumors in various parts of the body, including the sebaceous glands. Common areas in the body for additional tumors in Muir-Torre syndrome patients include the colon and kidneys. If carcinoma is diagnosed, the patient should be examined for additional malignant tumors and be monitored to ensure that she does not have Muir-Torre syndrome.