Summary

Gradually increasing abaxial proptosis in a middle-aged female patient revealed a large well-defined cystic lesion behind the globe extending till the orbital apex. B scan ultrasound and CT findings were favouring a diagnosis of orbital hydatid cyst. Thus as a diagnostic/curative surgical protocol, the cystic lesion was removed in total. However, intraoperative gross specimen examination was not classical of hydatid cyst, thus a further histopathological evaluation was carried out, which confirmed the diagnosis of orbital schwannoma with extensive cystic degeneration. Postoperatively the clinical course was uneventful at the end of 1 year.