Also known as seborrheic verruca, most people will develop at least one seborrheic keratosis during a lifetime. Seborrheic keratosis is a common skin growth. It may seem worrisome because it can look like a wart, pre-cancerous skin growth (actinic keratosis), or skin cancer. Despite their appearance, they are harmless, benign and don't become cancerous. They are characterized as brown, black or yellow growths that grow singly or in groups and are flat or slightly elevated. Often they are mistaken for warts and generally no treatment is required unless the growth becomes irritated. However, because it look similar in appearance to precancerous growths, your dermatologist might biopsy the tissue to confirm the diagnosis.