Zygomatico-Coronoid Pseudoarthrosis Due to Osteochandroma of Coronoid Process: A Rare Entity

Osteochondroma of the coronoid process also known as Jacob’s disease, has rarely been reported in the literature and it posses a challenge as diagnosis may be overlooked in favour of other causes of limited mouth opening.  

This is a case report of an adult male patient who presented with restricted mouth opening in whom radiological imaging, especially 3D computed tomography, played a role in establishing the diagnosis of Jacob’s disease.  

An osteochondroma of the coronoid process of the mandible (Jacob’s disease) is a rare cause of restricted mouth opening and its diagnosis can be overlooked in favour of TMJ ankylosis. The CT scan plays an important role in diagnosis and in planning for surgery.