Merkel cell carcinoma is a rare type of skin cancer. It most often appears as a bump on the face, head or neck. Merkel cell carcinoma also is called neuroendocrine carcinoma of the skin.

Merkel cell carcinoma most often happens in people older than 50. Long-term sun exposure or a weakened immune system may raise the risk of getting this cancer.

Merkel cell carcinoma tends to grow fast and to spread quickly to other parts of the body. Treatment may depend on whether the cancer has spread beyond the skin. (https://www.mayoclinic.org/diseases-conditions/merkel-cell-carcinoma/symptoms-causes/syc-20351030)