An exostosis (plural: exostoses) is the formation of new bone on the surface of a bone. Exostosis can cause chronic pain ranging from mild to debilitatingly severe, depending on where they are located and what shape they are.
The overgrowth of outer ear canal bone is the body's way of protecting the ear drum from the frequent rush of cold water against it which commonly occurs with surfing. They develop over many years and result in infections, pain, plugging and hearing loss.
When used in the phrases "Cartilaginous exostosis" or "Osteocartilaginous exostosis", it is considered synonymous with Osteochondroma. Some sources consider the terms to mean the same thing even without qualifiers, but this interpretation is not universal.
