Merkel cell carcinoma


Merkel cell carcinoma, also called neuroendocrine carcinoma of the skin, is a rare form of skin cancer that presents with a nodule of bluish-red discoloration. It can be aggressive and often spread to other part of the body (metastasis). Merkel cell carcinoma is commonly found in older people, and people with long term exposure to sunlight or weak immune system.


The most common onset of Merkel cell carcinoma is the presence on skin of small bump (nodule) that grow rapidly without pain. The nodule may look like the same color of the skin, red, blue or purple which can usually be found on the head, face, or neck but it can also be detected on other parts of the body.

The lump may have the following characteristics:

  • Raised or dome-shaped
  • Looks like an acne or insect bite
  • The size is like a ten cent and grows rapidly
  • Feels firm, itchy, tender or sore

Consult your doctor if you have found any suspicious freckle or mole that has changed its shape, color, size or grows quickly or if it bleeds.


The cause of Merkel cell carcinoma is unclear. Cancer generally starts from the DNA mutation of the normal cell. The mutation of cell causes uncontrolled duplication resulting in a formation of a mass (tumor). Merkel cell carcinoma starts in the Merkel cells, which are located at the base of the outermost layer of the skin (epidermis). These cells are attached to nerve endings in the skin that receive the sensation of touch.

The cause of Merkel cell carcinoma has been associated to a virus found in the skin which does not show any symptoms called Merkel cell polyomavirus. Its role in causing Markel cell carcinoma is still unknown but other factors are strongly believed to pose higher risk of developing the disease.

Risk factors

The following are the risk factors of developing Merkel cell carcinoma:

  • Excessive exposure to ultraviolet light. Too much exposure to Ultraviolet (UV) light from the sun or from tanning beds, which destroys the genetic DNA of the skin cells.
  • Having weak immune system. Having HIV infection, taking immunosuppressant drugs or having chronic leukemia.
  • History of other skin cancers. Such as basal cell carcinoma, squamous cell carcinoma or melanoma.
  • Older age. It usually occur in people who are 50 years old or more but may also happen at any age.
  • People with light-colored skin. White skin pigmentation are most likely to have this disease than those with black complexion.