The most common type is the nodular basal cell carcinoma , a flesh-colored (cream to pink) round or oval translucent nodule with overlying small blood vessels and a pearly-appearing rolled border. This tumor slowly grows sideways. It may eventually ulcerate and form a crust over the center as it outgrows its blood supply.
A second type of BCC is the pigmented lesion . This is darker than the nodular type, appearing blue, brown or black. It may be similar in appearance to the very aggressive malignant melanoma tumor. Naturally, it is very important to distinguish between malignant melanomas and pigmented BCC.
A third type of BCC is the superficial type that appears as a red, often scaly, localized plaque. It is frequently confused with psoriasis or eczema. There is also a morphea or sclerosing type, a single, firm, ill-defined, slightly raised lesion that tends to be more difficult to recognize than the nodular, superficial and pigmented forms. If untreated, basal cell carcinomas may crust, ulcerate and sometimes bleed.
Squamous cell carcinoma (SCC) is the second most common form of skin cancer, affecting between 8,000 and 10,000 people each year in Canada. It arises from the cells that make the protective keratin of the epidermis (keratinocytes). These tumors usually occur in areas of sun-damaged skin and at sites of previous burns, scars or chronic ulcers. SCC usually appears as a red, scaling, well-defined plaque and may gradually develop an ulcer, a scaly crust or a wart-like surface. Eventually it can spread into the deeper or surrounding tissues. Squamous cell cancers are considered superficial when the upper part of the dermis is involved and infiltrative when the lower dermis and fat tissues under the skin (subcutaneous) are invaded.
