Osteochondromas comprise a significant portion of bony tumors and occur most frequently in the metaphyses of long bones, specifically the femur (30%), tibia (15-20%) and humerus (10-20%). While typically benign, they are of clinical importance as they can impinge surrounding structures such as nerves, ligaments, or blood vessels. We report here a novel case of a cranial osteochondroma found during cadaveric dissection in a graduate anatomy course in the Department of Physical Therapy, to our knowledge the first published example of an osteochondroma located on the external skull.

Osteochondromas are benign cartilage-capped bony tumors projecting from the external surface of a bone containing a marrow cavity continuous with the underlying bone. These tumorous growths progress slowly and rarely undergo malignant transformation; however they can impinge local structures such as nerves, blood vessels or tendons, and occasionally raise cosmetic concerns.