Photo on the left: 25-year-old man with Leontiasis ossea with frontal and maxillary bossing. Image credit Wikipedia. Photo on the right: Skull with leontiasis ossea or lion face. Image credit: Scott Haddow, Luigi Cattaneo Museum, Institute of Human Anatomy, Bologna, on Flickr
Leontiasis ossea, or lion face, is a historical term with no clinical significance used to characterize an overgrowth of the facial and cranial bones that can be caused by several diseases. Although lion face is most frequently associated with craniofacial fibrous dysplasia, this condition can also be caused by Paget’s disease, fibrous dysplasia, hyperparathyroidism, and syphilitic osteoperiostitis.
When a person has a disease that causes lion face, one or both maxilla will progressively grow, eventually effecting the eye orbits, mouth, nose and sinuses. Vision loss can result when the optic nerve is compressed by the overgrowth of bone; the bones can also interfere with breathing and eating. Rarely bones of the cranium can also be modified, which can cause cerebral pressure that can cause death.
The overgrowth of bone can be treated with conservative surgical and prosthetic techniques.
References
Jones, J; Gaillard, F. Leontiasis ossea. Retrieved on April 2, 2014 from: http://radiopaedia.org/articles/leontiasis-ossea
A special thank you to Scott Haddow for the use of the above image. Follow him on Twitter