Abstract
Introduction : A large number of disorders affecting the masticatory system can cause mouthopening restrictions. Among them is Jacob’s disease, characterized by restricted jaw movements and caused by pressure of the mandible coronoid process, which is longer than normal in size, on the posterior aspect of the zygomatic arch, together establishing new joint formation. Observation : We present a case report of a 29-year-old male patient presenting limited mouth opening. Inter-incisal maximum mouth opening was 5 mm. On panoramic radiograph an elongated coronoid process of the mandible was evident. Computed tomography (CT) scans showed the relationship between the exophytic mass and the inner surface of the zygomatic arch. An extra-oral coronoidectomy was performed. A mouth opening of 55 mm was achieved intra-operatively. The post-operative period was without complications. The histopathological diagnosis was osteochondroma. Discussion : The clinical, radiological and histopathological characteristics and surgical approach to Jacob’s disease are discussed. Conclusion : In a patient with a limitation of mouth opening, and without any temporo-mandibular joint disease, an examination of the coronoid process is required to identify hypertrophy ofthe coronoid process and to diagnose Jacob’s disease.
Highlights
Jacob’s disease is one of the numerous causes of reduction of mouth opening
It was first reported by Langenbeck in 1853 but it was Jacob, in 1899, who first described osteochondroma of the coronoid process forming a pseudoarthrosis between the coronoid process and the zygomatic arch
Coronoid process enlargement is a condition that can result from exostosis, osteoma, osteochondroma, chondroma, Fig. 5
Summary
Jacob’s disease is one of the numerous causes of reduction of mouth opening In addition to plain film radiographs and to have a clear idea about this hypertrophy of the coronoid process and its relationships with headjacent structures, a computed tomography (CT) imaging was performed This examination revealed a well-corticated exophytic protuberance projecting anteriorly and superiorly from the hypertrophied left coronoid process. Axial computerised tomography (CT) and coronal CT scans revealed the presence of a mushroom-shaped radiodense mass at the apex of the coronoid, the zygomatic arch was curved laterally by this bony outgrowth. It revealed a remodelling of the inner aspect of the zygomatic arch, resulting in a pseudoarticulation (Fig. 3)
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