An adult case of retropharyngeal cellulitis; diagnosis by magnetic resonance imaging.

We experienced an adult case of cellulitis in the prevertebral space with retropharyngeal and danger space, and, which was suspected to be due to a fish bone stuck in the throat. Its lesion could not be demonstrated on plain radiograph, postcontrast computed tomography, or laryngoscopy, but noncontrast magnetic resonance imaging demonstrated the lesion and was useful in assessing the efficacy of medication.