Merkel cell carcinoma is a rare and aggressive type of skin cancer that originates in the Merkel cells of the skin. Approximately 3,000 people in the United States are diagnosed with Merkel cell skin cancer in any given year.
Merkel cells are found deep in the epidermis, which is the top layer of the skin. They are what’s known as “neuroendocrine” cells, meaning they have responsibilities in both the nervous system and the endocrine system. Merkel cell carcinoma (MCC) develops when Merkel cells begin to grow uncontrollably.
Unlike other forms of skin cancer, Merkel cell skin cancer typically spreads quickly to other parts of the body and may recur after treatment, making it a deadlier form of cancer. With early detection and treatment, however, Merkel cell carcinoma can be treated successfully.
This form of skin cancer is sometimes also called MCC, Merkel cell cancer, or neuroendocrine carcinoma of the skin.
What causes Merkel cell carcinoma?
Like other types of skin cancer, Merkel cell carcinoma is primarily caused by exposure to ultraviolet (UV) radiation from the sun and artificial sources such as tanning beds. Certain factors can increase the risk of developing MCC:
- Advanced age
- Blond or red hair
- Blue or green eyes
- Fair complexion
- History of tanning bed use or severe sunburns
- Personal history of skin cancer
- Use of light therapy to treat skin diseases
- Use of organ transplant medications or immunosuppressants
- Weakened immune system
Among those diagnosed with Merkel cell carcinoma, 8 in 10 have Merkel cell polyomavirus. This common childhood virus doesn’t cause Merkel cell skin cancer in most people, but in those who develop this form of skin cancer, the virus turns off the genes that are supposed to suppress tumor growth.
What are the signs and symptoms of Merkel cell carcinoma?
Merkel cell carcinoma typically appears as a single lump on skin that’s been exposed to the sun. These skin spots are usually:
- Dome-shaped or otherwise raised
- Fast-growing
- Firm
- Itchy
- Painless or tender and sore
- Red or violet in color
In many cases, Merkel cell carcinoma may be similar in appearance to a pimple, a stye, or an insect bite.
How is Merkel cell carcinoma diagnosed?
If you have a skin spot that’s suspected to be Merkel cell skin cancer, your dermatologist or another medical provider will start with a thorough examination of your skin using a tool called a dermatoscope. Other tools may be used to confirm a diagnosis or stage the cancer.
- Biopsy of cells in an area of the skin
- Imaging, such as CT scans, ultrasound, or PET scans
- Palpation of the lymph nodes to determine if they’re affected
To confirm whether MCC has spread into nearby lymph nodes, a lymph node biopsy may also be performed to remove and analyze lymph nodes.
Merkel cell carcinoma treatment at NGMC
Treatment for Merkel cell skin cancer usually involves a combination of therapies. Your treatment plan may include surgery, radiation, chemotherapy, or immunotherapy based on your specific needs.
Surgery for Merkel cell carcinoma
Surgery is the first-line treatment for most types of skin cancer, including Merkel cell carcinoma. Two primary types of surgery may be used:
- Excision involves removing the tumor and a section of normal-looking skin around the tumor. The skin that’s removed is then examined under a microscope. If cancerous cells are found in the normal-looking skin, additional treatment may be needed.
- Mohs surgery removes the tumor and some surrounding skin in small layers. The skin that’s removed is then examined under a microscope. Mohs surgery will continue as long as there are cancerous cells in the examined skin.
Lymph node dissection may also be performed to remove nearby lymph nodes. These lymph nodes are then checked under a microscope for cancer cells.
In cases where Merkel cell carcinoma has invaded deep into the skin, patients may also need reconstructive surgery, which can be performed immediately following cancer removal or at any time afterward.
Radiation therapy for Merkel cell carcinoma
Radiotherapy is often used as adjuvant therapy, meaning after surgical removal of the tumor. Research has found that radiation therapy given within four weeks of surgery can help reduce the risk of cancer recurrence. Radiation therapy may also be given as a standalone treatment for early stage Merkel cell carcinoma or cancer that surgery can’t remove.
Chemotherapy for Merkel cell carcinoma
Less commonly, chemotherapy may be used as adjuvant therapy following surgery. Chemotherapy uses powerful medications to kill off cancer cells. These medications may be given orally or infused intravenously.
Immunotherapy for Merkel cell carcinoma
A type of immunotherapy known as checkpoint blockade therapy may also be used as adjuvant therapy after surgery. This therapy, which has been used since 2017, blocks molecules in the body that prevent T-cells from activating. As the drug blocks those molecules, T-cells can then attack and kill off cancer in the body. These medications are infused into the body intravenously.
Merkel cell carcinoma research
Because Merkel cell carcinoma remains rare, additional research is needed to learn more about the disease, including how to best diagnose and treat it. At NGMC, we help connect our patients with appropriate clinical trials that can enhance their care and innovate future care for the disease. Learn more about the current clinical trials we are participating in.
Cancer rehabilitation
Treatment for Merkel cell skin cancer can cause a number of health challenges, including skin irritation, weakness, joint pain, and fatigue. We offer specialized cancer rehabilitation services to help patients overcome the effects of treatment and maintain quality of life.
Patient navigation
A cancer diagnosis can quickly become overwhelming. If you’re uncertain about your next steps, turn to the team of patient navigators at NGMC. Reach out to our patient navigation program today to connect with a navigator.
Schedule an Appointment with a Dermatologist
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