Can Basal Cell Carcinoma Turn Into Melanoma?

Basal cell carcinoma does not progress into melanoma. Each is a separate and distinct type of skin cancer.

Basal cell carcinoma is the most common form of skin cancer and one of two major nonmelanoma skin cancer types (the other is squamous cell carcinoma). The cancerous cells originate in the lower layers of the epidermis, grow slowly and rarely spread to other parts of the body.

Melanoma is a rare but aggressive type of skin cancer that originates in the melanocytes. These skin cells, which are found in the deepest part of the epidermis, produce melanin, the pigment that gives the skin its color.

Do basal cell carcinoma and melanoma look different?

The first sign of basal cell carcinoma is usually a small white or flesh-colored skin bump that grows slowly and may bleed. On the other hand, the first sign of melanoma is often a noticeable change in a mole, such as:

• Asymmetry. The shape of one half of the mole does not mirror the other half.
• An irregular border. The edges of the mole may be ragged, notched or blurred, with the pigment appearing to spread into the surrounding skin.
• Uneven coloring. The mole may display shades of black, brown, tan, white, gray, red, pink or blue.
• An increase in diameter. There is a change in size, usually an increase. Melanomas can be tiny, but most are larger than the size of a pea (larger than 6 millimeters or about 1/4 inch).
• Evolution. The mole has changed over the past few weeks or months.

A skin biopsy is the only way to diagnose basal cell carcinoma or melanoma. A physician can remove a small portion of suspicious tissue, then send it to a lab to be analyzed under a microscope for evidence of cancer. Therefore, it is important to promptly discuss any unusual skin changes with a physician.

If you have been diagnosed with basal cell carcinoma or melanoma, a skin cancer specialist at Moffitt Cancer Center can offer a second opinion after reviewing your lab work, biopsies and images. Or, if you have a suspicious skin lesion, you can have it checked at Moffitt with or without a referral. To request an appointment, call 1-888-663-3488 or submit a new patient registration form online.