Merkel cell carcinoma is a rare, highly aggressive neuroendocrine skin cancer that metastasises very quickly. It occurs when Merkel cells in the outer layer of skin grow out of control and often appears as a single pink, red or purple bump that is usually painless. Merkel cell carcinoma is commonly located on the face, neck and arms.
Merkel cell carcinoma is the most lethal form of skin cancer. Even if diagnosed early and treated with surgery and / or radiotherapy, Merkel cell carcinoma has a high risk of returning, with up to 50% of patients experiencing recurrence within two years. Once a patient develops metastatic Merkel cell carcinoma, only 14% of patients will survive for five years.