What are the other Names for this Condition? (Also known as/Synonyms)

• Malignant Melanoma of the Mouth
• Malignant Melanoma of the Oral Cavity
• Malignant Melanoma of the Oral Mucosa

What is Oral Malignant Melanoma? (Definition/Background Information)

• A melanoma is a type of cancer that develops from certain cells called melanocytes. Melanocytes are cells that produce melanin; the pigment that gives skin its color
• Oral Malignant Melanoma is a very rare type of mucosal melanoma that develops from the mucus membrane lining the oral cavity. It is also described as a form of acral lentiginous melanoma that typically affects the hands and feet and the oral mucosa
• Primary melanomas affecting the oral cavity are very rare, and hence, it is important to distinguish it from metastatic mucosal melanoma of the mouth, originating at sites other than intraoral
• Oral Malignant Melanoma are diagnosed with the help of a biopsy and/or imaging studies, such as through MRI scan of the affected area. It is treated by surgically removing the tumor. Additionally, chemotherapy may be needed depending on how advanced the disease is at the time of diagnosis
• The prognosis of Malignant Melanoma of the Oral Cavity is generally poor, since it is an aggressive form of melanoma; most individuals do not survive over 5 years (50% of them do not survive over 2 years)

Who gets Oral Malignant Melanoma? (Age and Sex Distribution)

• The peak incidence of Oral Malignant Melanoma is 50-60 years for males, and 60-70 years for females. Thus, it is diagnosed at a slightly lower age in men than women
• The average age at diagnosis is about 55 years. However, younger adults can also be affected
• The condition can affect individuals of any race or ethnicity
• For unknown reasons, Malignant Melanomas of the Oral Cavity are more common among the Japanese (seen in higher frequencies); some studies show that 10% of all such cases are diagnosed in the Japanese population

What are the Risk Factors for Oral Malignant Melanoma? (Predisposing Factors)

• Presently, no clearly defined risk factors for Oral Malignant Melanoma or any predisposing exposures have been established
• Tobacco smoke and other inhaled carcinogenic compounds (cancer-producing substances) have been suspected in the development of this form of mucosal melanoma, but data do not support this as significant risk factor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Oral Malignant Melanoma? (Etiology)

The exact cause of Oral Malignant Melanoma is unknown. Some of the possibilities being considered include the following:

• Some studies have shown that both chemical and physical stimulation caused an increased production of melanocytes in the oral epithelium (lining of the inside of the mouth) resulting in pigmented (colored) lesions
• Mucosal melanomas most commonly involve changes in a protein, called KIT, which plays a key role in cell survival, proliferation, and differentiation

What are the Signs and Symptoms of Oral Malignant Melanoma?

The signs and symptoms of Oral Malignant Melanoma may include the following:

• The presence of pigmented lesions/masses inside the mouth. Some lesions may not be pigmented (called amelanotic melanoma)
• The most common site is the soft and hard palate followed by the gums (mostly the upper gums are involved). 4 out of 5 cases involve the palate and maxillary gingiva (lower gums)
• Rare cases of melanoma affecting the tongue is also noted
• Painful oral lesions that cause bleeding and ulceration
• Pain or difficulty during chewing or swallowing
• Oral Malignant Melanoma may be present with non-specific symptoms such as fatigue, loss of weight, loss of appetite, and nausea

How is Oral Malignant Melanoma Diagnosed?

A thorough medical history and a complete physical exam by a physician are crucial for the diagnosis of Oral Malignant Melanoma. This is followed by some tests which include:

• Biopsy of lesions: The sampling of cells, to observe them under a microscope for signs of cancer
• Sentinel lymph node biopsy is of little value in Oral Malignant Melanoma
• Imaging studies: MRI scan of the mouth is generally preferred
• If the melanoma is suspected to have metastasized (spread) to internal organs, imaging tests, such as X-ray, CT or MRI scan of the affected areas, may be carried out

Note: Lesions that are not pigmented are difficult to be clinically diagnosed (visual examination).

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Oral Malignant Melanoma?

Oral Malignant Melanomas are capable of spreading (metastasizing) to other areas, as the disease progresses. Common sites involved in metastasis include:

• Lungs
• Liver
• Brain
• Lymph nodes of the neck
• Intestines

How is Oral Malignant Melanoma Treated?

The treatment options for Oral Malignant Melanoma include:

• Surgical excision of the tumor with sufficient negative margin (surrounding non-cancerous normal area is also removed). This is the treatment of choice
• Chemotherapy: Usage of drugs to kill cancer cells is an adjuvant therapy for more advanced diseases with cancer spread. Side effects depend on the drug used and may include nausea, vomiting, hair loss, diarrhea, fatigue, increased risk of infection, mouth sores, and easy bruising
• Immunotherapy, using agents that boost the immune system, such as interleukin-2 and interferon alpha are effective only in a small percentage of the patients. Side effects include flu-like symptoms, fever, headache, muscle pain, etc.

How can Oral Malignant Melanoma be Prevented?

Presently, no clear predisposing factors have been established for this extremely rare cancer type. Besides, there is also no well-researched information on how Oral Malignant Melanoma develops. Hence, the exact steps for prevention of this cancer type have not yet been determined.

What is the Prognosis of Oral Malignant Melanoma? (Outcomes/Resolutions)

• Oral Malignant Melanomas are typically aggressive malignancies, and the outcomes are very poor; only half of those diagnosed live beyond 2 years. The estimated overall 5-year survival rate is between 10-25%
• Patients with melanoma positive lymph nodes have a lower 5-year survival rate at 16 %
• There are high chances of cancer recurrence even after treatment, especially within the first 3-years

Nevertheless, the prognosis depends upon a set of several factors, which include:

• Stage of tumor: With lower-stage tumors, when the melanoma is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage cancers, such as those with metastasis, the prognosis is poor
• Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
• Age of the individual: Older individuals generally have poorer prognosis than younger individuals
• The size of the melanoma: Individuals with small-sized melanomas fare better than those with large-sized ones
• Individuals with bulky disease have a poorer prognosis
• Involvement of vital organs may complicate the condition
• The surgical resectability of Oral Malignant Melanoma (meaning if the melanoma can be removed completely)
• Whether the cancer is occurring for the first time or is recurrent. Recurring cancers have worse prognosis compared to those that do not recur 
• Response to treatment: Melanomas that respond well to treatment have better prognosis compared to melanomas that do not respond to treatment
• Progression of the condition makes the outcome worse

An early diagnosis and prompt treatment of the condition generally yields better outcomes than a late diagnosis and delayed treatment.

Additional and Relevant Useful Information for Oral Malignant Melanoma:

Studies are on currently to develop targeted therapies that focus on the KIT gene mutation, commonly seen in mucosal melanoma. One such drug called imatinib mesylate, blocks the activity of KIT and has proven to be effective in the treatment of the condition.