Eosinophilic granuloma is an unknown etiological lesion, which is histopathologically characterized by diffuse eosinophilic and histiocytic infiltration in granulation tissues. Though this lesion may occur in the skull and soft tissue, involvement of the mucosa of maxillary sinus is extremely rare.
We have recently experienced one case of eosinophilic granuloma considered to have extended from alveolar bone of 6 to the mucosa of maxillary sinus in a 57 year-old man. Postoperative course was good and there was no recurrence seen after 5 months.