Maxillary odontogenic keratocyst with respiratory epithelium: a case report.

We report a case of odontogenic keratocyst with a respiratory epithelial lining and a malformed impacted tooth in the maxilla of a 39-year-old Japanese female who suffered from swelling symptoms for half a year. CT examinations revealed an air-filled cystic lesion with an impacted tooth crown in the maxillary bone which expanded to the nasal cavity as well as to the maxillary sinus. Histopathologically, the surgically removed cyst wall consisted of fibrous granulation tissue with a lining of parakeratinized squamous epithelium as well as ciliated pseudostratified epithelium and with retention of desquamated keratin materials in the lumen. The impacted tooth was malformed lacking a root portion. We discuss the frequency of respiratory epithelium in odontogenic keratocysts.