Endonasal Endoscopic Management of Pterigopalatine Fossa Hydatid Cyst Hydatid cyst (echinococcosis) is an infectious disease caused mainly by Echinococcus granulosus, a parasite transmitted by dogs and encountered 1st in the liver and then in the lungs. Involvement in the head and neck region is uncommon, and pterygopalatine fossa disease resulting from hydatid cyst is extremely rare, with only 4 reported patients. In this report, the authors present a patient with exophthalmus caused by a primary hydatid cyst and involving the pterygopalatine fossa which treated only with endoscopic endonasal approach. Address correspondence and reprint requests to Muhammet Fatih Gökmen, MD, Darende Hulusi Efendi Hospital, Zaviye District, Haci Hulusi Efendi, Street No 22, 44700 Darende, Malatya, Turkey; E-mail: mfatihgokmen@gmail.com Received 28 April, 2019 Accepted 11 May, 2019 The authors report no conflicts of interest. © 2019 by Mutaz B. Habal, MD.