While most melanomas appear in the skin, mucosal melanomas do not. Instead, they occur in the mucous membranes, or moist surfaces, of areas inside your body.

Melanoma occurs when there is abnormal or uncontrolled growth of the cells that cause pigmentation. However, mucosal melanomas are not always pigmented. Mucosal melanomas can appear in the following areas:

  • eyes
  • mouth
  • head
  • neck
  • respiratory tract
  • gastrointestinal tract
  • vagina and vulva
  • anus

Mucosal melanomas are rare. About 1 in 100 cases of melanoma is of the mucosal variety.

The staging for the progression of mucosal melanoma is vague because of how rare this type of melanoma is. The staging and survival rates vary based on the location of the mucosal melanoma. The locations for disease stages and survival rates are broken down into three major types: head and neck, vulvar and vaginal, and anorectal mucosal melanoma.

Staging for mucosal melanoma of the head and neck as well as vulval melanomas use the AJCC-TNM (The American Joint Committee on Cancer — Tumor, Node, and Metastasis) classification.

The AJCC-TNM stages for mucosal melanoma of the head and neck and vulva are as follows:

  • T3: Mucosal disease
  • T4A: Moderately advanced disease; tumor involves the cartilage, deep soft tissue, or overlying skin
  • T4B: Very advanced disease; tumor involves one or more of the following:
    • brain
    • dura
    • skull base
    • lower cranial nerves (IX, X, XI, XII)
    • masticator space
    • carotid artery
    • prevertebral space
    • mediastinal structures

Vaginal melanoma and anorectal mucosal melanoma do not have a specific staging system. Because of this, a basic clinical stage classification system is used for these types of mucosal melanoma. This clinical staging system is as follows:

  • Stage 1: The disease remains localized.
  • Stage 2: Nodes in the region or area around the disease become involved.
  • Stage 3: The disease becomes metastatic and involves distant areas and organs.

The survival rate of mucosal melanoma is based on those that survive a minimum of 5 years after they are diagnosed. The survival rate also varies by the location of the mucosal melanoma.

The approximate 5-year survival rates are broken down by location as follows:

  • head and neck: 12–30 percent
  • vulval: 24–77 percent
  • vaginal: 5–25 percent
  • anorectal: 20 percent

The symptoms of mucosal melanoma vary based on where they’re located. Some symptoms are often misdiagnosed as other conditions. For example, mucosal melanoma of the anus can be misdiagnosed as hemorrhoids because the symptoms are the same or very similar.

Some symptoms of mucosal melanoma may include:

  • head and neck areas — nose bleeds, bleeding lump, ulcers, loss of sense of smell, nasal obstruction, a discolored area in the mouth, dentures that stop fitting properly
  • anus or rectal areas — bleeding, pain in the area, diarrhea, constipation, a mass that is present
  • vaginal areas — vulvar discoloration, bleeding, itching, pain with intercourse or shortly after, discharge, a noticeable mass

Mucosal melanoma is not caused by exposure to UV rays like other melanomas. Most people with mucosal melanoma are over the age of 65, and the risk increases as age increases. The specific cause is still unknown since this type of melanoma is rare. However, there are risk factors that may lead to mucosal melanoma, but even those are not certain. Like the symptoms, the possible risk factors vary by the area where the mucosal melanoma is present. Some possible risk factors for mucosal melanoma may include:

In the areas in or near the mouth:

  • dentures that don’t fit properly
  • smoking
  • carcinogens in the environment that have been inhaled or ingested

In the area of the vulva or vagina:

  • genetics
  • viruses
  • chemical irritants
  • chronic inflammatory disease

In the area of the rectum or anus:

As mentioned previously, these are possible risk factors and scientists are still trying to find the specific cause of mucosal melanoma.

The primary treatment option is surgery. The surgery would remove the abnormal area or cells containing the melanoma. To make sure the melanoma does not return, your medical team may recommend radiation or chemotherapy. They may also recommend a combination of both after surgery.

Systemic therapies, such as immunotherapies and targeted therapies, may be treatment options for select patients.

There are situations where the melanoma is in an area or on a vital organ where it cannot be surgically removed. In these cases, your melanoma may be able to be treated with radiation, chemotherapy, or both without surgery.

The primary complication of mucosal melanoma occurs when it moves into the distant metastasis stage. At this stage, there are very few treatment options available. The survival rate also becomes very low. Other complications are due to the lack of early detection and diagnosis. These factors make it an aggressive form of melanoma.

There are also complications from the treatment options. These include the common possible complications you have from any surgical procedure, chemotherapy, or radiation therapy. Be sure to discuss the complications and side effects with your doctor before undergoing any treatment plan.

Mucosal melanoma is considered an aggressive form of melanoma. It’s considered aggressive because it’s usually not discovered until it’s already in an advanced stage. By the time it enters the advanced stages, the treatment options are limited. It also usually moves into metastasis soon after diagnosis. Therefore, the outlook for a diagnosis of mucosal melanoma is poor. However, the earlier it’s diagnosed, the better outcome and survival rate you may have.

Be sure to have regular medical checkups. Also, inform your doctor of any changes or concerns you have as soon as they arise. Studies and experimental treatments are being developed regularly. This means earlier detection may become possible. New treatment options may also become available.