Suraj Venna, MD, is board certified in dermatology. He is the founding director of the Inova Melanoma and Skin Cancer Center. Dr. Venna specializes in detecting and treating skin cancer.
Dr. Venna is also chair for the 2015 American Society of Clinical Oncology Melanoma Education Committee, the largest international meeting of oncologists. Read Dr. Venna’s profile.
Former President Jimmy Carter revealed recently that he was diagnosed with stage 4 metastatic melanoma. In a heartfelt press conference, Carter, 90, detailed his diagnosis: Doctors first found melanoma in the liver and then discovered it had traveled to his brain. Carter is scheduled to undergo stereotactic radiation treatment to the brain lesions followed with a systemic immunotherapy called anti-PD1. Immunotherapy is a specialized treatment that uses the body’s own immune system to help fight the cancer.
Melanoma Unknown Primary: A Rare Cancer
While I don’t have all of the details of Carter’s case, it seems that he did not have a prior skin melanoma diagnosis—an unusual situation. Usually, when melanoma spreads to internal organs, it begins from a melanoma that was first diagnosed in the skin. Then, the cancer travels through lymphatic system and the blood stream to reach the internal organs. Carter’s case is a rare presentation of metastatic melanoma. Doctors call it melanoma unknown primary (MUP), or melanoma presenting internally without a known skin melanoma.
MUP: Trying to Find the Source
When patients present with MUP, doctors undertake an exhaustive search to determine if the source of melanoma is from primary sites other than the skin. For example, perhaps it originated from ocular melanoma (melanoma in or around the eye) or mucosal melanoma, (melanoma that occurs on mucosal surfaces, the moist surfaces that line the body cavities). These are both rare primary types of melanoma that can also spread to internal organs.
In the vast majority of cases of MUP, we never find the primary source of the spreading melanoma cells. We believe this happens for several reasons:
- The immune system cleared up a prior skin melanoma that doctors can no longer visualize on the skin surface. During this time, however, the skin melanoma cells metastasized through the blood and lymphatic system.
- The patient had a prior diagnosis of a benign mole that in retrospect was cancerous.
- A current skin melanoma exists but doctors have not yet identified it.
- The cancer is a primary melanoma arising from internal organs and lymph nodes.
Considering his diagnosis—stage 4 melanoma—Carter is undergoing the most current treatment protocol with the best therapy for melanoma. This treatment offers him a reasonable chance of prolonging his life, especially if he responds to the anti-PD1 immunotherapy he will begin shortly.