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JAMA Dermatology Patient Page
July 31, 2019

Merkel Cell Carcinoma

Author Affiliations
  • 1Department of Dermatology, Vanderbilt University School of Medicine, Nashville, Tennessee
JAMA Dermatol. 2019;155(9):1096. doi:10.1001/jamadermatol.2019.2068
What Is Merkel Cell Carcinoma?

Merkel cell carcinoma (MCC) is a rare skin cancer that develops on sun-exposed skin. Typically, MCC appears as a rapidly growing, painless, bluish to red bump in fair-skinned men over 50 years old. Merkel cell carcinoma is an aggressive skin cancer, often spreading to the lymph nodes and distant organs. In terms of mortality, MCC is second to melanoma for number of skin cancer–related deaths. Other names of the disease include primary cutaneous neuroendocrine carcinoma, small-cell primary cutaneous carcinoma, and cutaneous trabecula carcinoma.

Merkel Cell Carcinoma Facts

  • Risk factors for developing MCC include male sex, fair skin, and immunosuppression (a weakening of the immune system either due to disease or medications).

  • The number of patients diagnosed with Merkel cell carcinoma has increased rapidly over the past few decades because people are getting more sun exposure, there is a growing number of patients with weakened immune systems, and there are now better ways to diagnose the disease.

  • Merkel cell polyomavirus (MCPyV) has been found in most MCC tumors. It is not known if the virus causes the skin cancer development. It has been proposed that prolonged sun exposure allows the virus to grow. The virus and sun’s rays lead to skin damage, resulting in cancer.

  • Though MCPyV is associated with MCC, the cancer is not contagious.

Diagnosis and Testing

  • A skin biopsy is needed to confirm MCC diagnosis.

  • Imaging studies may be performed to determine if distant metastasis has occurred.

  • Patient staging depends on the tumor size, lymph node involvement, and organ metastasis.

Treatment and Prognosis

The course of treatment for MCC includes surgical removal of the tumor and an associated draining lymph node known as the sentinel node. Additional treatment is needed if metastasis has occurred. Nonsurgical treatments include radiation, chemotherapy, and/or immune-based therapies. New medications can boost the patient’s immune system to destroy tumor cells.

Patients with tumors localized to the skin have the best prognosis. When metastasis occurs, the prognosis is typically poor. New therapies increasing the immune system’s ability to fight cancer cells have shown promising patient outcomes.

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For More Information

Section Editor: Courtney Schadt, MD
The JAMA Dermatology Patient Page is a public service of JAMA Dermatology. The information and recommendations appearing on this page are appropriate in most instances, but they are not a substitute for medical diagnosis. For specific information concerning your personal medical condition, JAMA Dermatology suggests that you consult your physician. This page may be photocopied noncommercially by physicians and other health care professionals to share with patients. To purchase bulk reprints, call (312) 464-0776.
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Article Information

Published Online: July 31, 2019. doi:10.1001/jamadermatol.2019.2068

Conflict of Interest Disclosures: No disclosures were reported.