Mucosal Melanoma

What is Mucosal Melanoma?

Mucosal melanoma is a rare, life-threatening cancer. Mucosal melanoma accounts for about 1.4% of all melanomas and 0.03% of new cancers.¹

Melanomas are tumors that develop when cells called melanocytes grow uncontrollably. These aggressive tumors are usually diagnosed in their advanced stages, which leads to a poor prognosis. 

Melanocytes produce the pigment in your skin and mucosa, which lines the inner surfaces of your body. This is why most melanomas are pigmented and appear on the skin and mucosa. 

Common locations for mucosal melanoma include:

• Nasal cavity
• Sinuses
• Oral cavity
• Vulva
• Vagina
• Rectum and anal canal
• Gastrointestinal tract

However, mucosal melanoma can develop in nearly any part of your body with a mucous membrane.

Symptoms of Mucosal Melanoma

Mucosal melanoma symptoms vary depending on where the tumor develops. By the time most people experience symptoms, the mucosal melanoma is usually advanced.

Mucosal Melanoma of the Oral Cavity

More than half of oral mucosal melanoma cases are first discovered during a routine dental examination.¹ 

Signs and symptoms may include:

• Mouth pain
• Loose teeth
• Bleeding mass or ulcer in the mouth
• Discolored oral tissue (pigmented lesions)
• Dentures that no longer fit properly

Sinonasal Mucosal Melanoma

About 80% of sinonasal mucosal melanomas are in the nasal cavity, including the septum and lateral wall of the nose.² 

Symptoms are usually indistinguishable from noncancerous nasal diseases, and may include:

• Nasal obstruction
• Persistent nosebleeds
• Facial pain
• Decreased sense of smell

Double vision and bulging eyes may occur in advanced stages.³

What Causes Mucosal Melanoma?

Unlike skin melanoma, ultraviolet (UV) exposure is not a risk factor for mucosal melanomas. And mucosal melanoma is not related to a family history of melanoma.¹

No preventable risk factors for mucosal melanoma have been confirmed.¹ However, some evidence suggests cigarette smoking may increase the risk for head and neck mucosal melanomas.⁷

Certain factors may increase your likelihood of having mucosal melanoma, including:

• Advanced age — most people with mucosal melanoma are 70 years old when diagnosed, and the risk increases with age. Oral mucosal melanoma usually develops in slightly younger people.
• Being female — more women have mucosal melanoma than men, which is likely due to the number of cases found in the female reproductive system.
• Being Caucasian — mucosal melanomas are more common in Caucasians than other racial groups.

How is Mucosal Melanoma Treated?

Diagnosis

If your doctor suspects you have mucosal melanoma, they’ll take a biopsy. This involves removing a sample of tissue for laboratory testing.

After they confirm a diagnosis, your doctor may order additional tests to learn more about the stage and severity of the disease. Tests may include:

• Ultrasounds
• Computed tomography (CT) scans
• Magnetic resonance imaging (MRI) scans
• Positron emission tomography (PET) scans
• Blood tests
• Additional biopsies

Surgery

Surgery is the most effective way to cure mucosal melanoma.¹ This involves completely removing the abnormal tissue. However, surgical intervention is difficult in many areas where mucosal melanoma develops. 

Tumor regrowth is common. Most people with mucosal melanoma die from the cancer, even if the entire tumor was removed.

Chemotherapy and Radiation

If surgery isn’t possible, your doctor may recommend chemotherapy, radiation therapy, or both. Alternatively, your doctor may recommend radiation after surgery to reduce the likelihood of tumor regrowth.

Additional Treatments

Research and clinical trials investigating new drugs offer the possibility of a mucosal melanoma cure. Current treatments that apply to mucosal melanoma include:

• Immunotherapy — these drugs strengthen your immune system to better fight cancer. They may be taken as oral pills or delivered intravenously (IV).
• Targeted therapy — these drugs target and block specific pathways based on mutations in the mucosal melanoma. They’re taken as pills or via IV.

Outlook and Survival Rate

Because early diagnosis is so difficult, most people with mucosal melanoma develop incurable metastatic cancer. 

Compared to skin melanoma, mucosal melanoma has a very poor prognosis. Five-year survival rates of both types of cancer at the time of diagnosis include:¹

• Mucosal melanoma — 14%
• Cutaneous melanoma — 90%

Getting regular checkups and dental exams may improve the chances of an early diagnosis. The outlook for mucosal melanoma may improve with further research and the development of new treatments.

Stages of Mucosal Melanoma

Staging for mucosal melanoma isn’t clearly defined because of how rare the disease is. Staging systems vary based on where in the body mucosal melanoma arises.

Head and neck mucosal melanoma uses a simple staging system that can apply to all cases.  

• T3 — Mucosal disease only
• T4a — Moderately advanced disease; tumor involves deep soft tissue, cartilage, or overlying skin
• T4b — Very advanced disease; tumor involves surrounding organs, blood vessels, and other structures

A more cohesive staging system will likely emerge as scientists learn more about mucosal melanoma.

Summary

• Mucosal melanoma is a rare type of cancer that develops on moist surfaces that line the inside of your body.
• Unlike skin (cutaneous) melanomas, mucosal melanomas aren’t related to risk factors like sun exposure.
• Mucosal melanoma occurs when pigment cells called melanocytes grow uncontrollably.
• Any mucous membrane in your body can develop mucosal melanoma, but common locations include the nasal cavity, sinuses, and oral cavity.
• Survival outcomes for mucosal melanoma are low, but a better understanding of the disease through research and clinical trials may help develop better treatment for this condition