Merkel cells are found at the base of the top layer of skin (epidermis). These cells share some features with nerve cells as they are located very close to nerve endings. Merkel cells help us sense light touch and feel details on an object’s surface.
Normally, cells in the body will grow and divide to replace old or damaged cells. This growth is usually precise. Once enough cells are produced to replace the old ones, normal cells stop dividing. Tumors occur when there is an error and cells continue to grow uncontrollably. Merkel cell carcinoma develops from Merkel cells.
Merkel cell carcinoma is a rare type of skin cancer. Successful treatment depends on age, stage and location of cancer and other factors.
What are the symptoms of Merkel cell carcinoma?
The first sign of Merkel cell carcinoma is usually a fast-growing, painless nodule (lump) on the skin. The nodule may appear skin-colored, red, blue or purple. Merkel cell carcinomas usually appear on areas exposed to sunlight including the face, head, or neck, but can appear anywhere on the body.
What are the causes of Merkel cell carcinoma?
While there are no clear causes of Merkle cell carcinoma, some risk factors may include:
- Age (usually develops at 65 years or older)
- Light-colored skin
- Weakened immune system
- History of other skin cancers
- Excessive exposure to natural or artificial sunlight (UV light)
In about 8 out of 10 cases, the Merkel cell polyomavirus (MCV) is found in the cancer cells. MCV is a common virus that most people are infected with as children. However, this link was only recently found and doctors are still trying to understand its implications.
How is Merkel cell carcinoma diagnosed?
First, your doctor will learn your and your family’s medical history and perform a physical exam.
Your doctor may refer you to a dermatologist (skin specialist). A dermatologist may perform a physical exam and also one or more of the following tests:
- Imaging tests such as CT, CAT, PET, MRI or X-ray
- Dermatoscopy (microscopic lens to see the skin closely)
- Biopsy (removing a tiny piece of tissue for examination)
To learn how severe the cancer may be, your doctor will classify it by stage and grade.
How is Merkel cell carcinoma treated?
Treatment for Merkel cell carcinoma may include surgery, chemotherapy and radiation therapy. Recently, immunotherapy (using your body’s own immune system to fight cancers) has also been used. Your treatment will depend on age, overall health, cancer stage, cancer size and location, and other factors.