Benign vs. Malignant?

Many of our patients come in for skin checks and have one or more skin biopsies (samples) performed to determine if a suspicious lesion is benign or malignant. How do we determine which lesions are worrisome? What elements of the patient’s history make us concerned for a malignant lesion? What does it mean when we reassure you that a lesion is benign? What about a malignant lesion – how worried should you be?

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A benign lesion or tumor is a noncancerous growth. Non-cancerous means it is unable to spread throughout the body. Benign lesions can be removed if they are irritated or bothersome, otherwise they are harmless.

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A malignant tumor has the ability to grow uncontrollably, metastasize (spread) to other areas of the body and invade normal surrounding tissue. Malignant tumors can bypass the body’s normal mechanisms to control cell growth and spread. As malignant tumor invades surrounding tissue and spread to other areas of the body, they cause destruction along the way.

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The most common malignant tumor of the skin is a basal cell carcinoma. They are locally destructive but rarely metastasize. They create a slow growing, non-healing sore on the skin. If left untreated they can be disfiguring and painful. Recently there has been much debate whether these “slow growing, nonlethal cancerous lesions” are being overtreated, especially in the elderly. I know I opted for more conservative treatments in my elderly patients and often deferred treatment if the lesions are small and not bothersome.

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One of the less common but more dangerous malignant tumor of the skin is melanoma. Even small lesions with no symptoms can eventually metastasize and be fatal. Many of my patients come in for other concerns like itchy rashes or sore, rough spots and we incidentally find a melanoma on their back or leg. This is why I encourage all my patients to have a once a year full body skin check. The most dangerous skin lesions are not necessarily the ones that bother them!

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What types of lesions should you be worried about?

• New or changing mole or one that looks different than other moles
• Non-healing sore or sore that heals and returns
• Brown or black streak under a nail
• Dome shaped growth