Four cases of extracranial abscess caused by sinusitis exacerbated by a foreign body

Background: Foreign bodies in the paranasal sinus is a relatively rare. Furthermore, most of foreign bodies in the paranasal sinuses occur in the maxillary sinus, and reports of foreign bodies in frontal sinus are few. Extracranial abscesses caused by sinusitis with foreign bodies is a rare, but it sometimes cause serious complications. We report four cases of extracranial abscess caused by sinusitis exacerbated by a foreign body.