Ali Reza Lotfi - Department of Otorhinolaryngology, Imam Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
Sina Zarrintan - Department of General and Vascular Surgery, Imam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
Masoud Naderpour - Department of Otorhinolaryngology, Imam Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
Mohammad Sokhandan - Department of Otorhinolaryngology, Imam Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
Ashraf Fakhrjou - ۳Department of Pathology, Imam Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
Amrollah Bayat - Department of General and Vascular Surgery, Imam Reza Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
Firouz Salehpour - Department of Neurosurgery, Imam Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
Hamid Djalilian - Department of Otolaryngology-Head and Neck Surgery, University of California, Irvine, Orange, CA, USA.

Introduction: A hydatid cyst of the head and neck is a very rare condition, even in areas where Echinococcus infestation is endemic.   Case Report: We report a rare case of primary hydatid cyst of the right maxillary sinus in a ۴۰-year-old man. The initial diagnosis of the presence of a cystic mass was the result of physical examination and computed tomography (CT) scan. We resected the cystic mass using the Caldwell-Luc procedure. A definitive diagnosis was confirmed by postoperative histopathologic examination.   Conclusion: Hydatid cyst of the maxillary sinus is an extremely rare presentation. However, this condition should be considered in differential diagnosis of cystic lesions of the maxillary sinus.

Cystic lesion, Echinococcus, Hydatid Cyst, Maxillary sinus, maxillofacial