How can I tell if I have skin cancer on my nose? I'm 23, and I've been in the sun my whole life. I didn't start using sun protection until I was in my late teens. The skin on my nose is uneven and has never completely healed.

Matt

Unfortunately, you cannot tell if it's a skin cancer. It takes years of training to be able to look at skin and decide whether or not a particular lesion is, possibly, a skin cancer.

Many physicians are adept at diagnosing and treating facial skin cancers. Most ENTs could help you, as could many primary-care physicians. However, dermatologists are the reigning czars of all things skin, so your best bet for a quick diagnosis would be to consult with a dermatologist. (Dermatologists are also experts at the diagnosis and treatment of diseases of the mucous membranes, hair and nails.) However, even a dermatologist cannot always diagnose a skin condition by visual inspection alone. When cancer is suspected, a biopsy is usually necessary to make the diagnosis. My recommendation is that you find a dermatologist.

I also want to take this opportunity to discuss skin cancer. The three most common skin cancers are basal cell carcinoma, squamous cell carcinoma and malignant melanoma. Basal cell carcinoma is the most common and least deadly of the three. Sun exposure is certainly the most important risk factor for basal cell carcinoma, as these cancers tend to involve sun-exposed skin. Other risk factors include chronic skin injury, a weakened immune system and certain inherited diseases.

One "nice" feature of basal cell carcinoma is that metastasis (spread to other parts of the body) is extraordinarily rare. Nevertheless, basal cell carcinomas can be locally aggressive. Indeed, an outdated name for this cancer is "rodent ulcer," indicating the ability of the tumor to eat a hole in just about anything, given enough time!

Basal cell carcinoma can appear as a raised nodule with smooth, shiny borders and a central ulcer or crust. However, the appearance of basal cell carcinoma varies greatly, so it is impossible to give a blanket description for all tumors of this type.

Squamous cell carcinomas have the same risk factors as basal cell carcinomas. They are less common than basal cell carcinomas, but they have the ability to metastasize. The risk of metastasis is low for most squamous cell carcinomas (1 to 3 percent), but squamous cell carcinoma of the lip is an important exception, with an overall risk of metastasis as high as 12 percent. Large lip cancers are at even higher risk. As with basal cell carcinoma, squamous cell carcinoma can have many different appearances. It can appear as a scaly, rough patch of skin or as a non-healing ulcer.

Malignant melanoma is the third most common skin cancer and is easily the most deadly. Early recognition and removal are vital to a cure. Melanoma is a tumor of the pigment cells (melanocytes), and thus melanomas may exhibit a variety of colors (red, white, blue, green, black and all intermediate shades). The tumor border is typically irregular. Melanomas are rarely flat. Usually there is a bumpy, ulcerated or warty area within the suspicious region. Finally, not all melanomas are pigmented. "Amelanotic" melanomas conspicuously lack pigment.

Not all pigmented skin lesions are malignant melanomas! However, differentiating melanoma from other pigmented lesions is truly the domain of the dermatologist. Once again, biopsy is often essential to make the diagnosis.

What's the take-home message? Skin cancers are very treatable, but early diagnosis and treatment are ESSENTIAL. In the case of basal cell carcinoma or squamous cell carcinoma, prompt treatment could prevent the lesion from growing so large that removal could be disfiguring. In the case of malignant melanoma, prompt treatment could very well save your life.

See a dermatologist!