What is Mucosal Melanoma?

Mucosal melanoma is a rare and aggressive type of melanoma skin cancer that forms in the moist inner lining of certain body cavities and organs, such as the mouth, nasal passages, throat, digestive tract, urinary tract and genital area. Usually, the cancer begins in the pigment-producing cells (melanocytes) that give the tissue its color.

Mucosal melanoma is less common than skin (cutaneous) melanoma, accounting for only about 1-2% of all melanoma cases. It is often diagnosed at an advanced stage, making it more challenging to treat.

Mucosal melanoma causes

Mucosal melanoma occurs when the melanocytes in a mucous membrane undergo harmful DNA changes that cause them to grow uncontrollably. Excess abnormal cells then build up, bind together and form tumors.

The precise cause of the cellular mutations that lead to the development of mucosal melanoma is not well understood. Scientists believe it may be related to a combination of genetic, environmental and lifestyle factors.

Mucosal melanoma risk factors

Although exposure to ultraviolet (UV) radiation from the sun and indoor tanning devices is a well-established risk factor for cutaneous melanoma, it does not appear to play a significant role in the development of mucosal melanoma, mainly because mucosal surfaces are not usually exposed to UV radiation.

However, researchers have linked mucosal melanoma to certain genetic mutations and other factors that can increase the risk of melanoma, such as:

• Fair skin that burns or freckles easily
• Naturally blonde or red hair
• Blue or green eyes
• A family history of melanoma
• Exposure to certain chemicals, such as those commonly used in the textile and leather industries

Mucosal melanoma symptoms

The symptoms of mucosal melanoma can vary depending on the location of the tumor, such as the:

• Oral cavity (mouth) – A dark-colored lesion or lump inside the mouth that may bleed or cause pain
• Nasal cavity and sinuses – Nasal congestion or obstruction, nosebleeds and numbness in the face
• Digestive tract – Blood in the stool, abdominal pain, changes in bowel habits and unexplained weight loss
• Genital area – A dark-colored lesion or lump on the genitals or anus that may bleed, itch or cause pain
• Urinary tract – Blood in the urine, urinary frequency or urgency and pain in the abdomen or back

Mucosal melanoma diagnostic testing

Mucosal melanoma is usually diagnosed through a combination of a clinical examination, imaging test and biopsy. During the clinical exam, a physician will ask about the symptoms and examine the affected area of the body. To identify or rule out a tumor, the physician may order imaging tests, such as computed tomography (CT), magnetic resonance imaging (MRI) or positron emission tomography (PET) scans. If a tumor is present, the images can help the physician assess its location, size and spread.

A biopsy is necessary to confirm a diagnosis of mucosal melanoma. During this procedure, a physician will remove a small sample of tumor tissue for microscopic examination by a pathologist, who can identify cancerous cells. If a diagnosis of mucosal melanoma is confirmed, the physician may order further testing to stage the tumor and plan treatment.

Mucosal melanoma treatment

Treatment for localized mucosal melanoma usually involves surgical removal of the tumor, which may be followed by chemotherapy or radiation therapy. Advanced (metastatic) mucosal melanoma that cannot be surgically removed may be treated with radiation therapy alone.

Compared to cutaneous melanoma, mucosal melanoma does not respond as well to approved immunotherapies.

Benefit from world-class care at Moffitt Cancer Center

If you would like to learn more about mucosal melanoma, you can request an appointment with a specialist in Moffitt’s comprehensive Cutaneous Oncology Program by calling 1-888-663-3488  or submitting a new patient registration form online. We do not require referrals.