Craniomaxillofacial features in hereditary multiple exostosis.

Hereditary multiple exostosis is the most common form of bone dysplasia. This entity is also known as diaphyseal aclasis, hereditary deforming chondrodysplasia, multiple hereditary exostoses, multiple osteochondromatosis, multiple cartilaginous exostosis, dyschondroplasia, and Ehrenfried disease. It is an inherited autosomal dominant disease with predominance in males and a benign condition characterized by the presence of multiple exostosis or osteochondromas arising from long and flat bones.Osteochondroma is the most common benign tumor in persons between 10 and 30 years of age. It accounts for 20% to 50% of all benign tumors and 10% to 15% of all bone tumors. It is more commonly located at the level of the metaphysis of long bones. However, osteochondroma is rare at the level of the facial bones and skull base. It has been reported in the maxillary sinus and in different parts of the mandible, such as the condyle, ramus, body, and symphyseal region. It is very uncommon in the coronoid process and occipital bone.Jacob disease, or osteochondroma of the mandibular coronoid process, is a benign skeletal tumor that is rare in the oral and maxillofacial skeleton. A review of the literature revealed only 41 histologically proven cases of 52 reported cases. To the best of the authors' knowledge this is the first clinical report of bilateral coronoid osteochondroma and associated occipital exostosis in a patient with hereditary multiple exostosis.