Melanoma of the Head and Neck
What is melanoma of the head and neck?
Melanoma is a cancer that arises from melanocytes, the cells that give skin its pigment or color. Melanoma most commonly occurs in skin cells, but can rarely also occur in mucous membranes of the respiratory, gastrointestinal, genital or urinary organs. Melanoma arising in skin cells is caused by ultraviolet radiation from exposure to the sun and tanning beds.
Melanoma is the least common form of skin cancer, but it is responsible for more deaths per year than all other skin cancers combined. Melanoma is also more likely than other skin cancers to spread, and may be harder to control. However, approximately 75% of melanomas are found before they have spread, and can be cured with treatment. Mucosal melanomas make up 1% of all melanomas, and are more likely to spread to other sites
What are the symptoms of melanoma of the head and neck?
Melanomas usually present as an abnormal mole or growth on the skin. Many people have normal moles that are small, even, tan or brown in color, round or oval, and either flat or raised. Melanoma arises from abnormal melanocytes, or pigment cells, that become cancerous. These are usually brown or black in color because of melanin production by melanocytes. Any change in size of a mole, or the appearance of a new mole, should be evaluated for the “ABCDE” rule:
- A=Asymmetry: The appearance or shape of one half of the mole does not match the other side.
- B=Border irregularity: The mole has irregular or uneven borders, particularly if they are ragged or notched.
- C=Color variation: Variation in color throughout the lesion, with patches of different shades of brown or tan in a mole, is concerning.
- D=Diameter: Lesions that are larger than ¼ inch, or the size of a pencil eraser, may represent melanoma; however, melanomas can be smaller than this.
- E=Evolving: A lesion that changes in size, color, shape or texture is suspicious for melanoma.
Melanomas may also have the appearance of a wart, crusty spot, ulcer, mole or sore. It may or may not bleed or be painful. If you have a preexisting mole, any change in the characteristics of this spot — such as a raised or irregular border, irregular shape, change in color, increase in size, itching or bleeding — is a warning sign of melanoma. Sometimes the first sign of head and neck melanoma is an enlarged lymph node in the neck.
Normal moles in the head and neck often resemble each other. Any mole that is new or looks different from the others should be evaluated. Regular self-examination will help you determine if a mole is new or changing.
Mucosal melanoma of the head and neck most commonly arises in the sinonasal tract or oral cavity. It can present as discoloration in the mouth; a painless, bleeding mass; ulceration; ill-fitting dentures; nasal obstruction, particularly if on one side; or frequent nose bleeds.
What are the risk factors for melanoma of the head and neck?
- Sun exposure.
- Tanning bed exposure.
- Immunosuppression, either from a medical condition or by medications (such as those taken by transplant patients).
- Fair skin.
- Numerous moles.
- Previous skin cancer.
- Genetic predisposition: A family history of melanoma increases your risk.
How is melanoma of the head and neck diagnosed?
Diagnosis is made by clinical exam and a biopsy. Melanoma is diagnosed by the presence of abnormal melanocytes.
Melanoma of the skin is staged based on how deeply it invades the skin layers and whether or not it has spread. A superficial or shave biopsy will not provide the accurate staging information used to guide treatment. The depth of invasion determines the risk of spread to lymph nodes or other organs. Ulceration and microsatellitosis are additional diagnostic features that, when present, are associated with a higher risk of spread. In patients without clinically enlarged lymph nodes, sentinel lymph node biopsy is used to determine if microscopic spread to lymph nodes in the neck has occurred, and is used for all but very thin (less than 0.8-millimeters-thick) melanomas unless other high-risk features are present.
This information is used for staging, to guide prognosis and further treatment. Thick melanomas (greater than 4 millimeters deep) are associated with a higher risk of spread to other organs, which is evaluated by pretreatment imaging. When enlarged lymph nodes are detected on clinical exam, a fine needle aspiration biopsy is performed to determine whether melanoma is present in nodes.
Some subtypes of melanoma may be less likely to spread: lentigo maligna and desmoplastic melanoma. The role of sentinel node biopsy is controversial in these cases, and will be discussed with you by your treatment team.
Unlike cutaneous (skin) melanoma, mucosal melanoma is not staged by depth of invasion. Because the rate of distant spread is high, pretreatment imaging is part of mucosal melanoma evaluation.
Melanoma of the Head and Neck Treatment
Surgical resection with wide margins and often sentinel lymph node biopsy is required for melanoma that has not spread. Thin tumors, up to 1 millimeter thick, can be resected with 1-centimeter (half an inch) margins around the tumor. The greater the depth of invasion, the larger the margin required, up to 2 centimeters. Mohs surgery is not suitable for melanoma because the diagnosis often requires special pathologic staining that is not part of the Mohs technique.
To obtain a sentinel lymph node biopsy, a preoperative sentinel node localization study is performed: A radionuclide tracer is injected in the melanoma, then a radionuclide uptake SPECT or SPECT-CT scan shows which nodes the tracer spreads to first. These “sentinel” nodes may or may not contain melanoma: They are the nodes that a melanoma that has spread would first encounter, and contain melanoma cells when melanoma has spread to lymph nodes. Because there are hundreds of lymph nodes in the head and neck, your surgeon will use a gamma probe at surgery to identify and confirm that the nodes selected for removal are the sentinel nodes.
When enlarged lymph nodes are present, a neck dissection is performed at the time of surgery. If distant spread is detected during the workup — that is, melanoma has spread to other organs — immunotherapy and sometimes radiation therapy are used for treatment.
After surgery, systemic therapy — immunotherapy or targeted chemotherapy and sometimes radiation therapy — may be required based on the risk of recurrence and spread. The determination of whether or not you need such “adjuvant” therapy is based on the final pathology report findings. If microscopic melanoma is found in sentinel nodes, your doctor will discuss surveillance with neck ultrasound or neck dissection based on the pathologic features.
Patients whose melanoma has spread to other organs are treated with systemic therapy, with or without radiation therapy. Clinical trials are also available to test new and emerging therapies.