Overview
Name
Merkel Cell Carcinoma
Type
Skin Cancer
Merkel cell carcinoma is a very rare cancer that forms from abnormal Merkel cells located in the upper layer of the skin (epidermis). Because Merkel cells are close to nerve cell endings in the epidermis, sometimes Merkel cell carcinoma is classified as a “neuroendocrine” tumor. It is a highly aggressive cancer which can spread to other areas of the body including the lymph nodes, lungs, brain, and bones, even when diagnosed at an early stage. It is second only to melanoma in causing death. The number of cases diagnosed in the U.S. each year is approximately 2,500, far less than the number of cases of non-melanoma skin cancers. However, it has been reported that the incidence (annual number of cases) has continually increased over the last three decades.
These cancers tend to occur on sun-exposed areas of skin, especially on the face, head, and neck. But they can also develop on the skin of the trunk, arms, and legs and elsewhere, such as the genitalia and buttocks. Appearing as a firm reddish, pink, blue, or purple bump or nodule, they are generally painless and fast growing. They may be mistaken for benign conditions, such pimples, insect bites, cysts, and other benign growths. However, some Merkel cell carcinomas appear as hard patches on the skin. White males older than age 50 and those with weakened immune systems are at higher risk. Overall risk factors include UV exposure (including UVA treatment for psoriasis) and immunosuppression due to disease (HIV, blood cancers) or treatment with immunosuppressant drugs (organ transplants). Recent research suggests that a rare virus may be implicated in some but not all Merkel cell carcinomas but additional research is needed to determine what, if any role the virus has in the development of this cancer.
Because of the very aggressive nature of Merkel cell carcinomas, any new, firm, rapidly growing growth, especially those that are not symptomatic (bothersome) or painful, should be followed up promptly with a dermatologist.
All photographs and diagrams are intended for informational purposes only and are not intended to be used for diagnosis. A dermatologist should be consulted for examination and diagnosis of skin lesions.
Images
