Carcinoma and melanoma are forms of skin cancer with differentiating characteristics in appearance, prevalence, symptoms and fatality. Skin cancer is the most common form of cancer, and knowing the differentiating characteristics of both types of skin cancer makes identification easier when making a diagnosis.
Skin carcinoma occurs in the outer layer of the skin and is categorically considered as the most common type of cancer, with basal cell carcinoma as its most common form. It involves the development of a benign tumor that may appear on a localized area of the skin. Melanoma is the malignant form of skin cancer involving the pigment-producing cells in the skin. It is the most dangerous form of skin cancer as it not only affects the skin pigment but may eventually involve other organs in the body as the cancer cells spread.
Carcinoma on the skin appears as a small, shiny nodule on the areas commonly exposed to sunlight, usually on the neck, arms, face, head, hands and forearm. Small blood vessels sometime occur superficially on the nodules. It may sometimes appear as raw, dry skin on the chest and the tumor grows slowly in a course of months or years. Spread to other parts of the body is also rare. Although skin carcinoma is the most common form of skin cancer, it is the least fatal as it grows slowly and less likely to spread to other areas of the body.
Melanoma usually grows with the appearance of a small, pigmented skin and likely to occur on a pre-existing pigmented mole. Appearance may vary from flat and irregular brown patches of black spots to a raised brown patch with red, black, blue or white spots. Melanoma is less prevalent but takes the more progressive type and can easily spread to other areas of the body.
Cancer cells in melanoma forms from the cells producing the skin pigments while carcinoma affects the skin with its point of origin coming from the epidermis, the outer layer of the skin.
Heredity, exposure to UV radiation and weakened immune system are predisposing factors for carcinoma and melanoma to occur. Individuals with fair skin that easily burns and freckles easily are at risk to melanoma and carcinoma. However, the presence of abnormal moles and a history of blistering sunburn during childhood or teenage years increase the risk to melanoma.