What exactly is a congenital nevus, anyway?

In the most general terms, it’s essentially a mole present at birth.

Most doctors seem to classify them according to size. For example, an article on eMedicine.com uses the following classifications:

• small ( <1.5 cm)
• medium (1.5 cm-19.5 cm)
• large/giant (>20 cm, or covering more than 5% of the adult body).

In addition to the size variations, you’ll find nevi in numerous colors, shapes, and textures. They generally grow in proportion to the rest of the body and may change significantly in color over time. For instance, this picture, taken seconds after Ani was born, shows the redish tint her nevus started with. You can see in the Gallery that it’s now brown.