Genital warts, however, are contagious. The overwhelming majority of warts are harmless. The most common types don't become cancerous. Only rare types and some that infect the uterine cervix and the penis very rarely become cancerous. A wart's ultimate size and shape depend on the particular virus that caused it and its position on the body.
Warts often disappear without treatment.
However, some persist for many years, and others disappear and then come back. When doctors examine a growth on the skin, they try to determine whether it's a wart or some other growth. Some growths that may look like warts are actually skin tags, moles, corns, calluses, or even skin cancer. Warts are classified by their position and shape. They may spread, but common warts are never cancerous.