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Genetic and Rare Diseases Information Center (GARD)

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Merkel cell carcinoma

Other Names for this Disease
  • Carcinoma, merkel cell
  • Merkel cell cancer
  • Merkle tumors
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What is Merkel cell carcinoma?

What causes Merkel cell carcinoma?

What is Merkel cell carcinoma?

Merkel cell carcinoma is a rare type of skin cancer that appears as a painless, hardened, red to purplish bump.  It occurs primarily in sun-exposed skin of the head and neck, though it can also occur on the skin of the arms, legs, and trunk.  It is considered fast-growing (aggressive), meaning that it can spread quickly to surrounding tissues, nearby lymph nodes, or more distant parts of the body.  Merkel cell carcinoma is diagnosed by biopsy, when some of the tissue is removed and examined under a microscope.  In 2007, approximately 1500 people in the United States were diagnosed with this type of cancer.  Treatment depends on the size of the cancer and the extent to which it has spread as determined by imaging studies.[1]
Last updated: 5/28/2011

What causes Merkel cell carcinoma?

The exact underlying causes of Merkel cell carcinoma (MCC) are unknown; however, researchers have identified risk factors that are strongly associated with the development of MCC. Having one or more risk factors does not mean that a person will develop MCC; most individuals with risk factors will not develop MCC. Factors that have been associated with MCC include:[2][3]

    -being over 65 years of age
    -having fair skin
    -having a history of extensive sun exposure
    -having chronic immune suppression, such as after organ transplantation or having HIV. However, most people who develop MCC are not immune suppressed.[2]

In 2008, researchers discovered that a specific virus called Merkel cell polyomavirus (MCPyV) is frequently involved in MCC.[2] MCPyV has been detected in about 80% of tumors tested and associates with the DNA of tumor cells in a way suggestive of being involved in tumor development.[2][3] It is thought that the virus causes gene mutations that lead to MCC when immune function is defective.[3] Several additional studies have validated these findings.[2]

Last updated: 6/4/2013

  1. National Cancer Institute. General Information about Merkel Cell Carcinoma. Merkel Cell Carcinoma Treatment. 2011; Accessed 5/22/2011.
  2. Merkel Cell Carcinoma. May 8, 2013; Accessed 6/3/2013.
  3. Mathew Ludgate. Merkel cell carcinoma. DermNet NZ. May 22, 2013; Accessed 6/4/2013.