There are three major forms of skin cancer, each named for the cell where the cancer originates.

Basal Cell Carcinoma (cancer) forms from the cells that make up the basal layer of the epidermis.  They are usually caused by cumulative exposure to sunlight over several years.  They are the most common skin cancer, four times as common as Squamous Cell Carcinoma. Basal Cell Carcinoma appears as a pearly flesh-toned to pink bump, sometimes with dilated small blood vessels or ulceration.  Basal Cell Carcinoma grows locally does not spread through the body.

Squamous Cell Carcinoma forms from the cells above the basal layer, the squamous layer of the skin.  Squamous cell Carcinoma is also caused by sun exposure.  Its appearance is usually an angry red thickened area of the skin with a crusty scale that sometimes peels off and comes back.  Squamous Cell Carcinoma can spread throughout the body (metastasize).  Metastasis is more common from certain areas such as the head and neck, more so than the torso or extremities.

Melanoma skin cancer forms from the melanocytes, the cells that produce skin pigment called melanin.  (There is no difference between “Melanoma” and “Malignant Melanoma.”  They are the same thing. ) Melanoma usually appears as a funny colored flat mole.  (However, it can occur as a red or flesh-toned bump.)  The hallmarks of melanoma are summarized by the ABCDE’s of skin exam.

A = Asymmetry. One side of the mole does not look like the other.  You cannot cut it like a pie and always have two matching pieces.

B = Border Irregularity. The border is not smooth, it may have small jagged edges or a notch or look like a map of the coastline.

C = Color variation.  A benign lesion should have the same color all the way across.  Colors such as Black, Red, White, Blue, or two colors of Brown in the same lesion are suspect.

D = Diameter greater than a pencil eraser.  Lesions wider than 6 millimeters (a #2 pencil eraser for those of us in the United States!) are suspicious.

E = Evolution. A change in size, color, thickness or a lesion that becomes itchy, “burns” or bleeds is suspicious.  A new mole after the age of 50 has a 25% chance of being a melanoma.  Thus, we ask anyone over 40 with a new mole to come in to have it checked.