Merkel Cell Carcinoma Staging

Physicians use a different staging system for Merkel cell carcinoma than they do for other types of skin cancer. By creating a classification system that adequately reflects the unique growth patterns exhibited by Merkel cell carcinomas, physicians are able to better assess and treat these unusual malignancies.

Under the Merkel cell carcinoma staging system, cancers are classified as either:

  • Stage 0 (in situ primary tumor) – These cancers have not spread beyond the original location.
  • Stage 1A – These cancers are smaller than two centimeters and a tissue test has confirmed that there is no cancer in the lymph nodes.
  • Stage 1B – These cancers are smaller than two centimeters and a physical exam suggests that there is no cancer in the lymph nodes, but this has not been confirmed through pathological testing.
  • Stage 2A – These cancers are larger than two centimeters and a tissue test has confirmed that there is no cancer in the lymph nodes.
  • Stage 2B – These cancers are larger than two centimeters and a physical exam suggests that there is no cancer in the lymph nodes, but this has not been confirmed through pathological testing.
  • Stage 2C – These cancers have grown into the bones, muscles or cartilage beneath the original lesion, but have not grown into the regional lymph nodes
  • Stage 3A – These cancers have started to undergo micrometastasis (they have started to spread through the lymphatic system, but newly formed tumors are too small to be detected)
  • Stage 3B – These cancers have started to metastasize, but the newly formed tumors are smaller than two centimeters in size. 
  • Stage 4 – These cancers have spread outside the regional lymph nodes and signs of cancer may be present in distant organs

At Moffitt Cancer Center, our oncologists can expertly diagnose any patient who presents with the signs of Merkel cell carcinoma, then stage the cancer following a diagnosis, as we have extensive experience treating even the rarest forms of skin cancer. Appointments are available with or without a physician’s referral.

Our oncologists can provide additional information about the Merkel cell carcinoma staging process and the treatment options available for metastatic and non-metastatic skin cancers. To schedule a consultation, call 1-888-663-3488 or submit a new patient registration form online.