National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Merkel cell carcinoma


Other Names:
Merkel cell cancer; Merkle tumors; Carcinoma, merkel cell; Merkel cell cancer; Merkle tumors; Carcinoma, merkel cell; Cutaneous neuroendocrine carcinoma See More
Categories:
Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer. It usually develops as a single, painless, bump on sun-exposed skin. The bump may be skin-colored or red-violet, and tends to grow rapidly over weeks to months. It may spread quickly to surrounding tissues, nearby lymph nodes, or more distant parts of the body. Factors associated with developing MCC include increasing age, fair skin, a history of extensive sun exposure, chronic immune suppression, and the Merkel cell polyomavirus. This virus has been detected in about 80% of people with MCC.[1][2] Treatment may include surgery, radiation therapy, and/or chemotherapy. Treatment options and prognosis depend on the location(s) and size of the cancer, whether it has just been diagnosed or has come back (recurred), and how deeply it has grown into the skin.[1]
Last updated: 3/9/2017

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
100% of people have these symptoms
Merkel cell skin cancer 0030447
30%-79% of people have these symptoms
Cellular immunodeficiency 0005374
Chronic noninfectious lymphadenopathy 0002730
Cutaneous photosensitivity
Photosensitive skin
Photosensitive skin rashes
Photosensitivity
Sensitivity to sunlight
Skin photosensitivity
Sun sensitivity
[ more ] 		0000992
Erythematous macule 0025475
Erythematous plaque 0025474
Regional abnormality of skin 0011356
Skin nodule 0200036
5%-29% of people have these symptoms
Basal cell carcinoma 0002671
Carcinoid tumor 0100570
Lymphoid leukemia 0005526
Multiple myeloma 0006775
Squamous cell carcinoma of the skin 0006739
1%-4% of people have these symptoms
Abnormal brain FDG positron emission tomography 0012658
Brain neoplasm 0030692
Neoplasm of the outer ear
Outer ear tumor
0040095
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Last updated: 7/1/2020
Cancer is caused by changes (mutations) in the DNA inside of cells.[3] These mutations cause the cells to grow and divide into new cells, when they should not. The mutations that cause MCC are not inherited from a parent, but occur by chance during a person's lifetime (they are acquired, or somatic mutations). In many cases, it is not known what directly causes these mutations to occur. However, several factors are thought to increase the risk for mutations to occur - such as exposure to sunlight.[7331][2]

Merkel cell polyomavirus is frequently involved in the development of MCC and is present in about 80% of MCC tumors tested. While the majority of people have been exposed to this virus by adulthood, it appears that the virus does not cause any symptoms except in the very rare situations in which it leads to MCC.[2]

Other risk factors that have been associated with MCC include:[1][2]
  • being older than age 50
  • having fair skin
  • having a history of extensive sun exposure
  • having chronic immune suppression (e.g. organ transplantation or HIV)

Having one or more risk factors does not mean that a person will develop MCC. Most people with risk factors will not develop MCC.[1]

Last updated: 3/9/2017
MCC does not seem to run in families.[3] While DNA changes (mutations) found in the cells of MCC tumors can lead to MCC, these types of mutations are not inherited from a person's parents. They are referred to as somatic mutations and occur during a person's lifetime, often as random events.
Last updated: 3/9/2017

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Merkel cell carcinoma. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Organizations Providing General Support

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Financial Resources

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • The American Cancer Society provides detailed information about Merkel cell carcinoma. Click on the link to access this information. 
  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.
  • The Merck Manual provides information on this condition for patients and caregivers. 
  • The National Cancer Institute provides the most current information on cancer for patients, health professionals, and the general public.
  • SkinCancerNet is a comprehensive online skin cancer information resource developed by the American Academy of Dermatology. Click on the link to view information on Merkel cell carcinoma.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Merkel cell carcinoma. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • Is Merkle cell carcinoma hereditary? See answer

  • My brother recently passed away from Merkel cell carcinoma. How long would it have taken from the very first stage to an advanced state or death? See answer

  • Can you catch this cancer from a husband that you are close to and kiss every day? See answer

  • When staging Merkel cell carcinoma with sentinel lymph node biopsy, is the use of a tracer as effective as blue dye for identifying the sentinel lymph node?  What is the role of Mohs surgery for treating Merkel cell carcinoma? See answer


  1. General Information About Merkel Cell carcinoma. National Cancer Institute. July 22, 2016; https://www.cancer.gov/types/skin/patient/merkel-cell-treatment-pdq.
  2. Causes of Merkel cell carcinoma. merkelcell.org. February, 2017; https://merkelcell.org/about-mcc/causes-of-merkel-cell-carcinoma/.
  3. What Causes Merkel Cell Carcinoma?. American Cancer Society. April 13, 2015; https://www.cancer.org/cancer/merkel-cell-skin-cancer/causes-risks-prevention/causes.html.