Odontogenic Sinusitis

History: 50 year old man with headache. 

Odontogenic sinusitis: Coronal CT image of the face reveals a periapical lucency near one of the right maxillary molars (yellow arrow). Note the mucosal thickening in the right maxillary sinus (green arrow) as a result of the adjacent inflammation.

This is a case of odontogenic sinusitis, which is inflammation in a sinus adjacent to odontogenic infeciton or sinusitis as a result of sinus entry during dental surgery. The differential diagnosis includes sinus disease of other origins such as fungal sinusitis or bacterial superinfection after a viral URI, or mutliple mucous retention cysts.

Odontogenic sinusitis is diagnosed on CT when there is mucosal thickening in a sinus adjacent to an inflamed tooth, whether there is a dental carie, or in this case, a periapical lucency suggestive of a periapical abscess. It is treated with tooth extraction and antibiotics.

A root showing an abscess at the apex after extraction. (Photo credit: Wikipedia)