When clumps of melanocytes, the pigment-containing cells of the skin, normally occur, they form benign growths commonly known as moles. If melanocytes become malignant, however, melanoma, the most deadly type of skin cancer, ensues. In the United States, approximately 7,000 melanoma-related deaths are reported and 90,000 new cases of the disease are diagnosed annually.

Melanoma is much more likely to be fatal than other forms of skin cancer because the disease tends to spread to other areas of the body (metastasize) early in its development. Abnormal melanocytes tend to grow downwards, enabling them to invade deeper tissues and eventually some cells may break away and enter the lymphatic or circulatory system, which facilitate their travel to new locations.

Most commonly, melanoma metastasizes via regional lymph nodes. When nodal involvement occurs in a patient with melanoma, the disease is said to be in stage III, and when distant metastases have already formed the cancer is considered a stage IV disease. In order that melanoma can be detected in earlier stages of the disease, when it is more readily treatable, those that are at risk should regularly screen their skin for any new growths or any changes in preexisting moles.

Once melanoma has metastasized the cancer is associated with a very poor prognosis. The outlook is worst for those who have several different organs with metastases, while it is somewhat better for patients with metastatic cancer restricted to a single site, even when this site is affected by multiple tumors. Metastatic melanoma present solely in one of the lungs is especially more promising than many other forms of metastatic cancer. This is because pulmonary metastases are often surgically resectable, which makes long-term survival more possible.

The primary risk factor for melanoma is excessive exposure to the ultraviolet radiation of the sun. Individuals with light skin, hair, and eyes are especially susceptible to the effects of the sun’s rays and should take extra precautions against skin cancer, which may include regularly utilizing sunscreen, staying indoors midday when the sun is most intense, and wearing hats and protective clothing. Other notable melanoma risk factors include a family history of the disease, the presence of atypical moles (dysplastic nevi), and being employed in certain occupations, particularly those that require regular exposure to ultraviolet radiation.

Metastatic Melanoma in Lung Tissue at 20x Magnification - Any notable alteration in symmetry, border shape, size, or coloration of a mole should be of special concern and be brought to the attention of a medical professional.

Metastatic Melanoma in Lung Tissue at 40x Magnification - When metastatic melanoma cannot be adequately treated with surgery or radiation therapy, systemic approaches such as chemotherapy and immunotherapy are commonly utilized.

Metastatic Melanoma in Lung Tissue at 10x Magnification - In recent years, there has been particular interest in the link between severe childhood sunburns and melanoma, though damage to the skin at any age is unhealthy.