What is Sebaceous Gland Carcinoma?
Sebaceous carcinoma, or SC, is a rare type of skin cancer that originates from the oil-producing glands in your skin, known as sebaceous glands. This kind of cancer mostly affects areas near the eyes, head, and neck. However, it can also develop in any part of the body that has sebaceous glands.
Sebaceous carcinoma can either start on its own or accompany a condition known as Muir-Torre syndrome. This syndrome is a variant of another condition called Lynch syndrome, which is marked by skin tumors and several types of internal cancers, with the most common ones affecting the digestive system.
The concerning aspect about SC is it has an aggressively damaging nature. It can form in multiple sites locally causing destruction and can sometimes spread in a pattern called pagetoid spread, which is difficult to detect. On top of that, this cancer can easily spread to other parts of the body, a condition medically referred to as distant metastasis. Because of these reasons, SC is seen as a very aggressive disease that significantly impacts a person’s health and carries a high risk of mortality.
What Causes Sebaceous Gland Carcinoma?
Sebaceous carcinoma (SC), a skin cancer that originates in oil-producing sebaceous glands, often occurs close to the eyes. This is because the sebaceous glands, which are modified forms of Meibomian glands – tiny oil glands along the edge of the eyelids, are found there. SC can also originate from the Zeiss glands, near the base of the eyelashes, and the sebaceous glands in the ocular caruncle, the small pink spot in the corner of the eye.
Most sebaceous carcinomas occur due to spontaneous genetic mutations. Sometimes they can also form from harmless sebaceous growths, but this seems to be rare. In cases like the Muir-Torre syndrome, sebaceous carcinomas are caused by a lack of certain DNA repair genes, leading to unstable DNA regions. However, sebaceous carcinomas that happen randomly, not associated with any syndrome, do not show evidence of lost DNA repair genes or unstable DNA regions.
Risk Factors and Frequency for Sebaceous Gland Carcinoma
Sebaceous carcinoma, or SC, tends to be more common in older women. Although it is rare among individuals of the white race, in the Asian population it counts for up to 28% of all eyelid cancers. Worldwide, SC occurs at a rate of 1 to 2 instances per million people per year. Almost all sebaceous carcinoma cases (more than 98%) are found in people over the age of 40. The highest rate of occurrence comes during the seventh and eighth decades of life. Only a small number of childhood cases have been documented. White patients are about three times more likely to develop this type of cancer than non-white patients. When it comes to where the cancer appears, it is usually found in the upper eyelid due to the greater number of meibomian (oil-producing) glands in that area.
- Individuals with a history of radiation exposure.
- Individuals with a weakened immune system.
- Individuals with a genetic disorder called Muir-Torre syndrome.
Signs and Symptoms of Sebaceous Gland Carcinoma
Sebaceous carcinomas, a type of skin cancer, often appear on the eyelids (in about 40% of cases) and especially on the head or neck (in 80% of the cases). When they form on the eyelids, these cancers usually seem like a hard, growing lump. They’re more commonly found on the upper eyelid because that area has more sebaceous (oil) glands. Sometimes they can present with swelling and thickening of the eyelid, mimicking conditions like chalazion and blepharitis, causing a delayed diagnosis. If left unchecked, the cancer can spread to larger areas of the eye, even reaching the orbit and nearby structures.
When sebaceous carcinomas are found in places other than the eyes, they usually look like a yellowish lump and can sometimes have ulceration. The neck and head are the most common places for these types of cancers, but they can also appear on the trunk and limbs. It’s rare, but in some cases, these cancers have been reported to develop in internal organs like the parotid gland, breast, ovaries, and prostate.
Testing for Sebaceous Gland Carcinoma
If you have eye inflammation that is on one side (unilateral) and isn’t getting better, or if you have an eyelid lump (like a stye or chalazion) that doesn’t go away or keeps coming back even after treatment, it could be a sign of a sebaceous carcinoma (SC). A sebaceous carcinoma is a type of skin cancer that often occurs around or on the eyes. To confirm the diagnosis, you might need an incisional biopsy. This procedure involves taking a small sample of tissue to check for the presence of cancer.
The best treatment for sebaceous carcinoma involves complete removal of the tumor by surgery. This is called an excisional biopsy. It involves the removal of the tumor with some healthy tissue around it. This ensures that no cancer cells remain, and it can also help confirm the diagnosis. After the removal, the sample will be stained with hematoxylin and eosin – chemicals used to highlight the cell’s structure – and observed under a microscope to understand the extent of the cancer.
Immunohistochemistry, another type of test that identifies specific proteins in cells, may be used to confirm the diagnosis and differentiate between SC and similar skin cancers. When it comes to SC, the majority of these cancers demonstrate a positive reaction to certain proteins – EMA, ADP, and AR – almost 100% of the time.
Even though most of these cancers occur by chance (sporadically), some medical professionals recommend genetic testing if you’re diagnosed with this cancer as it may be linked to a condition known as Muir-Torre syndrome.
Your doctor will need to thoroughly examine your eyes and the surrounding areas to check for any signs of the disease. They’ll also feel the areas around your ear and neck for any swollen lymph nodes, which could indicate the cancer has spread. If the cancer appears to be widespread or if enlarged lymph nodes are found, your doctor may recommend imaging tests for your head, neck, and other parts of the body to see how far the cancer has spread. If there are any suspicious lymph nodes, a fine-needle aspiration biopsy can be performed. This procedure involves drawing out a sample of cells from the lymph node with a thin needle to check for cancerous cells.
Treatment Options for Sebaceous Gland Carcinoma
The central aim of treating a type of cancer known as “sebaceous carcinoma of the head or neck” is to surgically remove the tumor completely. Two common types of surgery that are usually employed for this purpose are “wide local excision,” a procedure where the surgeon aims to remove all of the cancerous tissue, and “Mohs micrographic surgery,” a precise surgical procedure used to treat skin cancer.
In some cases, if the cancer affects the tissue that covers the front part of your eye, known as the conjunctiva, the treatment can include various methods such as cryotherapy (which uses extreme cold to destroy diseased tissue), surgical removal of the affected area of the eye, or a topical application of a chemotherapy drug called mitomycin C.
If it is not possible to surgically remove the cancer, for example in cases where the cancer has spread to cover a large area of the eye or has extended into the eye socket, removal of all the eye’s contents, a procedure called “orbital exenteration,” is often necessary.
One might also wonder about the role of radiation therapy in treating sebaceous carcinomas. However, this is somewhat uncertain. While some small studies have reported positive results from the use of radiation as the primary treatment of this type of eye cancer, surgery remains the most common method of treatment.
In addition to surgery and potentially radiation, other supplementary treatments can include cryotherapy and the use of topical mitomycin C again. These techniques are mainly used when the cancer has spread to the conjunctiva, a condition known as “pagetoid spread.”
What else can Sebaceous Gland Carcinoma be?
There are several harmless and dangerous conditions that might be mistaken for Sebaceous Carcinoma (SC). These tumors can often appear to be like chalazion, which is a lump in the eyelid, particularly when they cause pain or swelling, do not respond to typical treatment, or recur after being removed through surgery. There is a long list of different types of eyelid lumps that may be considered when diagnosing SC apart from the most common one, chalazion. These include:
- Inclusion cyst
- Papilloma
- Keratosis
- Keratoacanthoma
- Dermoid cyst
Other conditions that resemble SC are benign sebaceous tumors like sebaceous adenomas. However, these harmless tumors are rarely seen near the eye. Other cancers like basal cell carcinomas, squamous cell carcinomas, and Merkel cell carcinomas could also have similar symptoms to SC. Therefore, examining the cells of the tumor under a microscope is crucial to making a correct diagnosis.
What to expect with Sebaceous Gland Carcinoma
Sebaceous carcinomas, a type of aggressive cancer, often spread to lymph nodes and other parts of the body. These are often found around the eyes and may come back in 11% to 30% of cases after being removed. They can also spread to other parts of the body in 25% of cases. For sebaceous carcinomas found on other parts of the body, they may come back and spread in 29% and 21% of cases, respectively.
They usually spread to the lymph nodes in the region of the tumor first. However, they can also spread to the lungs, brain, liver, small intestine, and urinary tract. The mortality rate for this type of cancer varies widely between 9% and 50%.
When it comes to survival rates after five years, those with the cancer in the eye region have a better chance of survival at 75.2%, compared to those with the cancer in other parts of the body at 68%.
Certain factors can make the prognosis worse. These include a tumor larger than 1 cm, poor differentiation (which means the cancer cells greatly differ from normal cells) under microscope examination, spread of the cancer into the blood vessels or lymph system, and cancer on both the upper and lower eyelid.
Possible Complications When Diagnosed with Sebaceous Gland Carcinoma
Sebaceous carcinoma, a type of skin cancer, can have several complications. These can include a return of the cancer, spread of the cancer to nearby areas, and even spread to distant parts of the body through the lymphatic system (a part of the immune system) or blood vessels.
Common Complications:
- Recurrence of the cancer
- Local invasion, or spread of the cancer to nearby areas
- Distant metastasis, or spread of the cancer to other parts of the body
- Spread of the disease to other parts of the body through the lymphatic system or blood vessels
Preventing Sebaceous Gland Carcinoma
There are no known lifestyle changes or actions that patients can take to prevent the development of sebaceous carcinoma, a type of skin cancer. However, patients diagnosed with Muir-Torre syndrome, a rare genetic condition that increases the risk of certain types of skin cancer, should be well-informed about this risk. It’s also important that they seek medical help if they notice any troublesome changes to their skin. In addition to this, patients suffering from long-term inflammation in the eye or eyelids should regularly visit an eye specialist for check-ups.
