Skin Cancer Pictures, Part IV: Non-Cancerous and Pre-Cancerous Skin Lesions

Although most moles are benign, there are certain types that carry a higher risk, especially for melanoma. About 30% of the population has moles called dysplastic nevi, which are larger than ordinary moles (most are 5 mm across or larger), have irregular borders, and are various shades or colors. Individuals who have dysplastic nevi plus a family history of melanoma (a syndrome known as FAMM) are at a high risk for developing melanoma at an early age (younger than 40). Similarly, giant congenital nevi (shown in the photo), are major risk factors for melanoma. In such cases, cancer usually appears by age 10.