Skip to main content
 

What is Merkel Cell Carcinoma?

Merkel Cells are found in the top layer of the skin. These cells are very close to nerve endings.

Also called neuroendocrine carcinoma of the skin or trabecular cancer, Merkel cell carcinoma is a very rare type of skin cancer that forms when Merkel cells grow out of control. Merkel cell carcinoma starts most often in areas of skin exposed to the sun, especially the head and neck, as well as the arms, legs, and trunk. Merkel cell carcinoma tends to grow quickly and to metastasize (spread). It usually spreads first to nearby lymph nodes and then may spread to lymph nodes or skin in distant parts of the body, lungs, brain, bones, or other organs.

Risk Factors

Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer. Likewise, not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for Merkel cell carcinoma include the following:

  • Being exposed to a lot of natural sunlight
  • Being exposed to artificial sunlight, such as from tanning beds or psoralen and ultraviolet A (PUVA) therapy for psoriasis
  • Having an immune system weakened by disease, such as chronic lymphocytic leukemia or HIV infection
  • Taking drugs that make the immune system less active
  • History of Cancer
  • Being male or white or over the age of 50

Diagnosis

Merkel cell carcinoma usually appears on sun-exposed skin as a single lump that is fast-growing, painless, firm and dome-shaped (or raised) and red or violet in color.

A doctor should be consulted immediately if changes to the skin are seen.

If a patient has symptoms that could be merkel cell cancer, the doctor will test for fever and high blood pressure and check general signs of health. The patient will likely have one or more of the following tests:

  • Physical Exam - An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken. 
  • Full-Body Skin Exam - A doctor or nurse checks the skin for bumps or spots that look abnormal in color, size, shape, or texture. The size, shape, and texture of the lymph nodes will also be checked. 
  • Biopsy - The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. Once the results from the test or procedure are returned you will be able to make thoughtful decisions

Stages

If Merkel Cell is diagnosed, the doctor needs to know the stage, or extent, of the disease to plan the best treatment. Staging is a careful attempt to find out whether the cancer has spread. Also, the doctor will perform more tests to identify if the cancer has spread to other areas of the body. Such tests may include imaging tests -- CT scan, magnetic resonance imaging (MRI), bone scan, or x-ray.

Stages of Merkel Cell Carcinoma

Stage 0 (carcinoma in situ)

In stage 0, the tumor is a group of abnormal cells that remain in the place where they first formed and have not spread. These abnormal cells may become cancer and spread to lymph nodes or distant parts of the body.

Stage I

Stage I is divided into Stage IA and Stage IB:

Stage IA - In stage IA, the tumor is two centimeters or smaller at its widest point and no cancer is found when the lymph nodes are checked under a microscope.

Stage IB - In stage IB, the tumor is two centimeters or smaller at its widest point and no swollen lymph nodes are found by a physical exam or imaging tests.

Stage II

Stage II is divided into Stage IIA, Stage IIB and Stage IIC:

Stage IIA - In stage IIA, the tumor is larger than two centimeters and no cancer is found when the lymph nodes are checked under a microscope.

Stage IIB - In stage IIB, the tumor is larger than two centimeters and no swollen lymph nodes are found by a physical exam or imaging tests.

Stage IIC - In stage IIC, the tumor may be any size and has spread to nearby bone, muscle, connective tissue, or cartilage. It has not spread to lymph nodes or distant parts of the body.

Stage III

Stage III is divided into Stage IIIA and Stage IIIB:

Stage IIIA - In stage IIIA, the tumor may be any size and may have spread to nearby bone, muscle, connective tissue, or cartilage. Cancer is found in the lymph nodes when they are checked under a microscope.

Stage IIIB - In stage IIIB, the tumor may be any size and may have spread to nearby bone, muscle, connective tissue, or cartilage. Cancer has spread to the lymph nodes near the tumor and is found by a physical exam or imaging test. The lymph nodes are removed and cancer is found in the lymph nodes when they are checked under a microscope. There may also be a second tumor, which is either: Between the primary tumor and nearby lymph nodes or farther away from the center of the body than the primary tumor

Stage IV

In stage IV, the tumor may be any size and has spread to distant parts of the body, such as the liver, lung, bone, or brain.

Treatment

Different types of treatment are available for patients with Merkel Cell Carcinoma. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. (A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer.)

Your treatment options depend on the stage of cancer, your overall health and your preferences about treatment. In metastatic disease, the location and extent of the Merkel Cell is also an important consideration.

You do not have to rush to make a decision, so consider the options carefully. Ask questions if you do not understand any aspect of treatment or the terms your doctors are using. Research shows that cancer survivors of all educational levels and backgrounds can have a hard time communicating with their health care team. One of the best ways to improve communication with your health care team is to prepare your visits so that you can best make use of the time.

A treatment plan is a way to deal with both the short and long term goals of managing your Merkel Cell Carcinoma. There are several treatment options for your cancer, depending on the cancer stage and the patient’s age and general health. Patients have time for second opinions and to talk through all of their options with their doctors and develop a treatment plan that best fits their needs.

Learn More About Treatments & Side Effects