Merkel Cell Carcinoma

1 What is Merkel Cell Carcinoma?

Merkel cell carcinoma or neuroendocrine carcinoma of the skin, is a rare type of skin cancer that mostly affects older people.

It is characterized by light pink brown or bluish-red lump in your face, head or neck. Having weakened immunity or prolonged sun exposure also increases your risk.

The cancer progresses rapidly and metastasizes (spreads) to different parts of your body. The choice of appropriate treatment is determined by the cancer stage. 

2 Symptoms

The earliest symptom of Merkel Cell Carcinoma is a nodule on face, head or neck, which is:

  • Rapidly growing
  • Painless
  • Bluish, purplish or reddish

Remember that the nodule can appear anywhere on your body including the regions that have no sun exposure.

When to see a doctor?

Consult your doctor if you observe changes in:

  • size,
  • shape
  • color

of mole or nodules. Also observe warning sign like easy bleeding.

3 Causes

The exact cause of Merkel cell carcinoma is not understood. Merkel cells make up the outermost layer of your skin (epidermis).

Nerves that carry touch sensations are in contact with the Merkel cells. Recent studies suggest a virus inhabiting human skin, Merkel cell polyomavirus, could be the reason behind this type of cancer.

However, more studies are required to establish the role of this virus.

4 Making a Diagnosis

Following tests are performed for diagnosis of Merkel cell carcinoma:

  • Physical exam: Your doctor will check if you have any growths on your skin, such as moles, freckles, pigmented spots or nodules.
  • Biopsy: Skin biopsy is a procedure in which a sample of suspicious skin is removed and sent to lab for further analysis to detect if there are any signs of cancer.

Tests for determining your cancer stage

Following tests or procedures are used:

  • Sentinel node biopsy: A sentinel node is a lymph node where your cancer may have just spread. Injecting a dye at a site near the cancer can predict a sentinel node as it runs into various nodes via your lymphatic system. The sentinel node is then obtained and viewed under microscope to check if it has cancerous cells. This test detects whether the cancer has metastasized to your lymph nodes.
  • Imaging tests:Imaging tests, such as a chest X-ray or a CT scan of your chest and abdomen can help your doctor detect if the cancer has spread to other parts of the body.
  • You may also need positron emission tomography (PET) scan or an octreotide scan, a non-invasive detection test that uses radioactive material.

5 Treatment

Following are the treatments available for Merkel cell carcinoma:


Surgery can remove the cancerous cells and small portion of nearby cells. Lymph nodes that are affected by cancer may also be removed (lymph node dissection).

If needed, a procedure called Mohs surgery can be used, which involves repetitive removal of each layer of tissues till no cancer is observed during microscopic analysis.

Radiation therapy

High energy beams, such as X-rays are directed to specific areas that contain cancer cells. It can be given after surgery to kill any cancer cells that have survived the surgery.

Radiation therapy alone is a choice for the patient who does not prefer surgery.


Chemotherapy uses oral or injectable cancer-killing chemicals. Chemotherapy is an option for patients with recurring or spreading cancer.

Follow-up care

Follow-ups are necessary to look for possible recurrence of the cancer or side effects of the treatment. The first few years of follow-ups examinations include monthly physical examinations. Then, the interval between exams is extended.

If your cancer was large or had spread to other body parts, you may need imaging tests such as PET/CT scans to detect recurrence.

Cancer survivors also need frequent self-examinations of skin and lymph nodes. Any new changes in your skin should be considered warning signs. Therefore you need to see your doctor in such case.

Consult your doctor if you experience any new persistent symptoms, such as

Recurrence of the carcinoma, if occurs, is usually within few years after treatment but it may reappear after many years. Also, people with persistent Merkel cell carcinoma need regular follow-ups.

Treatment for recurring carcinoma depends on the location of the cancer, your previous treatments as well as your health status. You are at increased risk of developing other type of skin cancer if you previously developed Merkel cell carcinoma.

Hence, it's a good idea to frequently examine your skin to check if there are signs of new skin cancers.

6 Risk and Complications

There are several risks and complications associated with Merkel cell carcinoma.


  • Overexposure to light: Exposure to ultraviolet from sun or tanning beds, can boost your chances of developing Merkel cell carcinoma. In most of the cases of Merkel cell carcinoma, the cancer develops on sun-exposed skin.
  • Compromised immunity: Risk is higher in people who have compromised immunity such as those with HIV infection, taking immunosuppressant or who have chronic leukemias.
  • Having other skin cancers in the past: A history of other skin cancers, such as such as basal cell or squamous cell carcinoma can make your more prone to Merkel cell carcinoma.
  • Age: The risk is higher in individuals above 50.
  • Fair skin: Whites are at increased risk as compared to black.


Spreading cancer (Metastasis): Unfortunately, treatments are not always successful in limiting this cancer. Initially, only the surrounding lymph nodes are affected but as the cancer advances, it can affect distant organs such as brain, bones, liver or lungs.

Metastasized carcinoma are life-threatening and difficult to treat.

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