Staging Melanoma
Stage IV Melanoma

Stage IV melanomas are associated with metastasis beyond the regional lymph nodes to distant sites in the body. The most common sites of metastasis are to vital organs (lungs, abdominal organs, brain, and bone) and soft tissues (skin, subcutaneous tissues, and distant lymph nodes).

Primary characteristics of Stage IV melanoma include:

  • Location of the distant metastases
  • Number and size of tumors
  • Serum LDH level. LDH is the abbreviation for lactate dehydrogenase, an enzyme found in the blood and many body tissues. Elevated LDH levels usually indicate that the tumor has spread to internal organs.
Subclasses of Stage IV Melanoma

Stage IV melanomas do not include any T or N classification:

  • M1a: the tumor has metastasized to distant skin, the subcutaneous layer or to distant lymph nodes. Serum LDH is normal.
  • M1b: the tumor has metastasized to the lungs. Serum LDH is normal.
  • M1c:
    • The tumor has metastasized to vital organs other than the lungs and serum LDH is normal, or
    • There are any distant metastases with elevated LDH
See also Stage IV Treatment.