Diagnosing Skin Cancer

CURE, Summer 2006, Volume 5, Issue 2

Skin cancers are almost always visible and easy to detect--if you're looking for them.

Unlike most other forms of cancer that develop within the body and require special diagnostic tools for detection, skin cancers are almost always visible. Regular examinations of the skin can therefore identify changes early. Though a dermatologist can provide an initial assessment of a suspicious area, a person’s primary care physician should be consulted when an irregular area is first noticed. From there, the physician may recommend seeing a dermatologist if the skin condition requires further evaluation or treatment.

Basal cell and squamous cell carcinomas are associated with typical appearances that aid in their identification. Basal cell carcinomas can appear as either a flat, pale area, or as a raised red or pink area with a translucent, shiny or waxy surface, possibly with blue, brown or black areas. Blood vessels may be visible, and the lesion may bleed easily following minor injury. Squamous cell carcinomas may grow as a flat reddish patch or in lumps. However, other suspicious changes that signal skin cancer include a sore that does not heal, scaly patches of skin or areas that are scar-like and firm. Doctors who believe a particular lesion looks suspicious will want to take a sample, or biopsy, of the region to be examined more closely by a pathologist.

Several different methods can be used to sample the area in question. For a shave biopsy, the doctor uses a surgical blade to shave off a thin layer of skin. In contrast, a punch biopsy may be performed to allow the doctor to sample a deeper layer. A special tool called a trephine, which looks like a miniature cookie-cutter, is used for this procedure to obtain a core containing all three layers of skin. Finally, an incisional biopsy may be performed in which a larger portion of the lesion is removed, or the entire lesion may be removed during an excisional biopsy. These procedures can be performed using a local anesthesia, and the choice depends on the type of cancer suspected and which method will provide the best sample to facilitate diagnosis.

Though rare, when it is suspected that the cancer has spread from the original skin site to nearby lymph nodes, the doctor may also perform a biopsy of the suspicious node. One method, called fine needle aspiration biopsy, uses a narrow needle to obtain small tissue fragments for examination. If the biopsy results are unclear, the entire lymph node may need to be surgically removed.