Merkel cell carcinoma
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Merkel cell carcinoma, also called neuroendocrine carcinoma of the skin, is a rare form of skin cancer that presents with a nodule of bluish-red discoloration. It can be aggressive and often spread to other part of the body (metastasis). Merkel cell carcinoma is commonly found in older people, and people with long term exposure to sunlight or weak immune system.
Symptoms
The most common onset of Merkel cell carcinoma is the presence on skin of small bump (nodule) that grow rapidly without pain. The nodule may look like the same color of the skin, red, blue or purple which can usually be found on the head, face, or neck but it can also be detected on other parts of the body.
The lump may have the following characteristics:
- Raised or dome-shaped
- Looks like an acne or insect bite
- The size is like a ten cent and grows rapidly
- Feels firm, itchy, tender or sore
Consult your doctor if you have found any suspicious freckle or mole that has changed its shape, color, size or grows quickly or if it bleeds.
Causes
The cause of Merkel cell carcinoma is unclear. Cancer generally starts from the DNA mutation of the normal cell. The mutation of cell causes uncontrolled duplication resulting in a formation of a mass (tumor). Merkel cell carcinoma starts in the Merkel cells, which are located at the base of the outermost layer of the skin (epidermis). These cells are attached to nerve endings in the skin that receive the sensation of touch.
The cause of Merkel cell carcinoma has been associated to a virus found in the skin which does not show any symptoms called Merkel cell polyomavirus. Its role in causing Markel cell carcinoma is still unknown but other factors are strongly believed to pose higher risk of developing the disease.
Risk factors
The following are the risk factors of developing Merkel cell carcinoma:
- Excessive exposure to ultraviolet light. Too much exposure to Ultraviolet (UV) light from the sun or from tanning beds, which destroys the genetic DNA of the skin cells.
- Having weak immune system. Having HIV infection, taking immunosuppressant drugs or having chronic leukemia.
- History of other skin cancers. Such as basal cell carcinoma, squamous cell carcinoma or melanoma.
- Older age. It usually occur in people who are 50 years old or more but may also happen at any age.
- People with light-colored skin. White skin pigmentation are most likely to have this disease than those with black complexion.
Diagnosis
The following tests are done to diagnose Merkel cell carcinoma:
- Physical exam. The doctor will examine your moles, freckles, skin pigmentation and other abnormalities on your skin.
- Skin biopsy. The doctor will remove a sample of suspicious skin tissue for examination under a microscope in the laboratory to look for any cancer cells.
Determining the extent of cancer
Stage of Merkel cell carcinoma may be determined using the following tests:
- Sentinel node biopsy. This technique injects a dye near the cancer which will run through the lymphatic system to check if the cancer has reached the lymph nodes.
- Imaging tests. Chest X-ray and a CT scan of your chest and abdomen will be suggested by the doctor to determine if the cancer has spread to other organs. Another test which may be done is Positron Emission Tomography (PET) scan or an octreotide scan. During PET scan, a radioactive tracer is injected to check if the cancer cells have spread.
Merkel cell carcinoma may be staged from 0 to IV. The lowest number indicates that the cancer is localized only in outer layer of skin (epidermis). If it has reached stage IV, it means that cancer has become advanced and has spread to other parts of the body (metastasis).
Treatment
These are the treatment options for Merkel cell carcinoma:
- Surgery. The tumor and some healthy skin around it may be surgically removed, including the lymph nodes if it has been found that the cancer has spread into them. A procedure called Mohs surgery may also be done by cutting the cancer using a scalpel. This technique analyzes a thin layer of skin under the microscope to check if cancer cells are present. If cancer cells are still present, the procedure is continuously done to remove them until cancer cells are no longer detected and the border of skin is tumor-free.
- Radiation therapy. A strong energy beam is used though X-rays and protons to kill cancer cells. The patient will lie down on the table and a large machine is navigated around the patient to target a specific area that is affected in the body. Radiation may be used after surgery to kill the remaining cancer cells after tumor removal. It may also be used alone to kill cancer cells that has spread to other areas of the body.
- Immunotherapy. Uses the body’s own immune system to kill cancer cells. It is commonly used to target Merkel cell carcinoma that has metastasized to other parts of the body.
- Chemotherapy. Uses medications administered orally or intravenously, or both, to kill cancer cells. It is uncommon to use chemotherapy in Merkel cell carcinoma but it may be used if the cancer has reached the lymph nodes or other body organs.
