Metastatic melanoma is a type of cancer that originates in the skin, specifically from pigment-producing cells called melanocytes. It can occur when these cells become malignant and grow uncontrollably, forming tumors that may spread to other parts of the body through the bloodstream or lymphatic system. When this happens, it is referred to as metastatic melanoma because the cancer has reached beyond its original site and affected other organs. This stage of melanoma is more difficult to treat than earlier stages, but advancements in therapies have improved survival rates for those with metastatic disease.