Case study of a rare occipital osteoma related to cranial trauma.

Burial 280 is a 31- to 40-year-old male Native American individual who lived in a 10^th to 16^th century coastal foraging society in California. His remains display a large ectocranial elevation on the occipital, measuring 23.3 mm anteroposteriorly, 25.3 mm mediolaterally, and is elevated to 20.1 mm. It is located along the superior nuchal line on the left side of the occipital and represents an extremely rare occipital localization of a particular type of trauma-related osteoma. In our prior study of Burial 280, trauma etiology was not considered; herein, we present evidence for such a cause. Such trauma-related neoplasms are sometimes called ballooned (or giant, depending on size) osteomas. The presence of this tumor appears to have resulted in asymmetrical cranial muscle use and consequent skeletal changes. This case study illustrates that cranial trauma may sometimes induce benign tumor elevations, rather than a depression or pronounced fracture.