Merkel cell cancer is an aggressive cutaneous cancer that grows very rapidly. Merkel cell cancer usually metastasizes first to regional lymph nodes. Merkel cell cancer is a highly aggressive tumor with a mortality rate that approaches 30% to 40% within 3 years of diagnosis.

• Merkel cell cancer is an aggressive cutaneous tumor that grows rapidly.
• Merkel cell cancer usually metastasizes to:
  • Lymph nodes
  • Liver
  • Lungs
  • Brain
  • Bones

Common complications of merkel cell carcinoma include:^[1]

• Neurologic complications which include:^[2]
  • Seizures
  • Bilateral radiculopathies
  • Myoclonus
  • Cauda equina syndrome
  • Altered mental status
• Leptomeningeal carcinomatosis

• Merkel cell cancer is a highly aggressive tumor with a mortality rate that approaches 30% to 40% within 3 years of diagnosis.
• If diagnosed early, merkel cell carcinoma has a good prognosis with a 5-year survival rate of approximately 90%.
• The prognosis depend on the following:^[3][4][5][6]
  • Stage at diagnosis (1st most potent prognostic factor).
  • Lymph node involvement (2nd most important prognostic factor).
  • Merkel cell polyomavirus (MCPyV) viral load also play an significant role in prognosis of merkel cell cancer.
  • Cancer location
  • Cancer depth
  • Primary vs recurrent
• Lymphovascular invasion in merkel cell cancer patients associated with poor prognosis.
• Intratumoral lymphocyte infiltration in merkel cell cancer patients associated with good prognosis due to presence of CD8+ lymphocyte infiltration.^[7]
• p63 expression in merkel cell cancer patients associated with poor prognosis.