Chondromyxoid fibroma of the mastoid invading the occipital bone.

We describe a case of chondromyxoid fibroma of the mastoid bone extending along the occipital bone in a 48-year-old man. The presence of this tumor was heralded solely by aural fullness caused by otitis media with effusion. The tumor arose from the mastoid cavity, eroding the entire petrous portion, and invading the foramen magnum and jugular foramen. The occurrence of this tumor is exceedingly rare, and, to our knowledge, this is only the second article in the literature that describes a chondromyxoid fibroma of the mastoid region. The clinical appearance of this tumor and its light- and electron-microscopic findings are presented with reference to other articles.