Basal cell carcinoma (BCC) usually occurs in a sun-exposed area of the skin. It usually appears as a round pink bump, although this depends on the type of BCC (e.g., superficial, nodular, or morpheaform). Over time, it's liable to grow, and after a few months or years it may be surrounded by tiny but visible blood vessels. It often has a tendency to repeatedly crust over, heal, and then crust over again. The crusting process may involve bleeding. If left alone, it may take on a very different appearance, as the cancer eats away at the skin. The result looks as if the skin has been chewed up, with bites taken out of it. Such a tumour is called a rodent ulcer.
Superficial BCC is the least aggressive type of BCC, while morpheaform BCC is the most aggressive and dangerous form. Superficial BCC grows out from the edge and causes damage in the surrounding tissues over time. Because superficial BCC grows slowly, people do not always ask their doctors for advice right away. Early detection and treatment is often the best way to increase the chances of a good outcome in many types of cancer. Nodular BCCs grow irregularly from their edges and often remain flat. Bleeding followed by crusting or scaling over occurs commonly with this type of carcinoma. Morpheaform BCCs grow quickly and are more difficult to treat.
Squamous cell carcinoma (SCC) generally begins as a small firm lump. Most SCCs grow from actinic keratosis (AK), which is a rough, scaly skin lesion that appears on sun-exposed areas. It may be the same colour as the surrounding skin, or it may be brown, pink, or red. AK is simply a change in size, shape, and organization of skin cells. Because they can lead to skin cancer, AKs should be found and treated early.
SCCs are often red, scaly, crusted, or ulcerated. They my be itchy and slow to heal. As the squamous cell tumour grows, the skin tends to degenerate and scar tissue appears. The tumour will bleed easily if scratched, though it's not usually painful. SCC is more likely to metastasize (spread to other parts of the body) than BCC. Luckily, early treatment can lead to a good chance of survival and cure.
Complications arise when the tumour reaches tissue needed for other purposes, such as the mouth, the anus, or the eye. Generally, cancers on mucous tissue (such as the lips) are more likely to metastasize. Cancer in the webs of the fingers or thumb, or before the first knuckle of a finger, is also more likely to metastasize. Metastasis is never very likely with these types of cancer, however.
While few people die of basal cell carcinoma and squamous cell carcinoma, untreated cancers can grow and produce disfigurement. Treatment will sometimes cause disfigurement if a large amount of skin has to be removed.