Melanomas are a type of cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs that develop from melanocytes, which are the cellsthe basic structural and functional unit of all living things that produce pigment, generally in the skin (cutaneous melanoma). However, they can also develop in the eye (ocular melanoma) and possibly other parts of the body. Mucosal melanomaa type of cancer that develops from melanocytes, which are the cells that produce pigment generally in the skin (but can develop in other areas of the body) refers to melanomas that occur in the mucosal surfaces of the body.
Mucosal membranes are protective membranes that line the internal structures of the body that are exposed to air, such as the respiratory, gastrointestinal, and genitourinary tracts. Their primary function is to produce and secrete mucous that lubricates the underlying tissues in the body, and traps foreign material such as bacteria.
Mucosal melanoma is more common in females, and is generally diagnosed in people over 70. However, anyone can develop this disease.
Types of Mucosal Melanoma
There are three types of mucosal melanoma, which are classified by the mucosal areas they develop in.
Head and Neck Mucosal Melanoma
Mucosal melanomas of the head and neck are the most common subtype of this disease. This type of mucosal melanoma generally presents in the nasal cavity, paranasal sinuses, and oral cavity; however, some cases have been reported in the pharynx, larynx and/or oesophagus. Unfortunately, the prognosisto predict how a disease/condition may progress and what the outcome might be for head and neck melanomas is usually poor.
Vulvovaginal Melanoma
Melanomas of the vulva and vagina are less common than those of the head and neck. As the name suggests, this type of melanoma develops in the mucosal membranes of the vulva and/or vagina of the female reproductive tract. Unfortunately, the prognosis for vulvovaginal mucosal melanoma is usually poor.
Anorectal Melanoma
Melanomas of the anusthe opening where solid waste (faeces or stool) exits the body and rectumthe last section of the large intestine/bowel that holds waste until it is ready to be removed from the body are a less common subtype of mucosal melanomas. This type of melanoma often develops in the transitional zone of the anal canal (the point where normal skin meets the mucus membrane), however they can also develop in the skin of the anal verge (the area where the anal canal meets the outside skin), the transitional epithelium of the anal canal (an area where the cells lining the rectum become transition into the cells lining the anus), or in the rectal mucosa. Unfortunately, the prognosis for anorectal mucosal melanoma are usually poor.
Treatment
If mucosal melanoma is detected, it will be staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancer cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumoura tissue mass that forms from groups of unhealthy cells) indicates the size and depth of the tumour.
- N (nodea small lump or mass of tissue in your body) indicates whether the cancer has spread to nearby lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissuea group of cells that work together to perform a function.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localisedaffecting only one area of body cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advancedat a late stage, far along or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for mucosal melanomas may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence, most commonly a wide local excisionremoval of cancerous tissue and a margin of healthy tissue around it to prevent cancer recurrence.
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Immunotherapya treatment that uses a person's immune system to fight cancer.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Risk factors
Because of how rare mucosal melanomas are, there has been limited research done into the riskthe possibility that something bad will happen factors of this disease. However, due to the locations that this disease develops in it is unlikely that exposure to ultra-violet (UV) radiation would be a risk factor.
Symptoms
The symptoms of mucosal melanomas vary with location.
Head and Neck
Symptoms of head and neck mucosal melanomas may include:
- Discolouration of the mouth.
- Painless and/or bleeding lump.
- Mouth ulcers.
- Dentures no longer fitting.
- Nasal obstructions.
- Persistent nose bleeds.
- Loss of smell.
Vulvovaginal
Symptoms of vulvovaginal mucosal melanomas may include:
- Vulva discolouration.
- Genital itching.
- Unusual vulvar or vaginal bleeding and/or discharge.
- Genital ulcers.
- A lump or massa growth of cells that come together to make a lump, may or may not be cancer on the vulva or vagina.
- Pain during/after intercourse.
Anorectal
Symptoms of anorectal mucosal melanomas may include:
- Anal bleeding.
- A mass on the anus.
- Anal or rectal pain.
- Changes in bowelportion of the digestive system that digests food (small bowel) and absorbs salts and water (large bowel); also called intestines habits, such as constipationa condition where a person has difficulty passing faeces/stools and diarrhoeafrequent discharge of watery or loose stools from the body.
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have a mucosal melanoma, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Imagingtests that create detailed images of areas inside the body tests, potentially including:
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- PET (positron emission tomography) scana type of medical imaging that uses radioactive tracers to create detailed images of the body.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Biopsyremoval of a section of tissue to analyse for cancer cells.
