title: Granular cell tumor of the orbit.
abstract: OBJECTIVE
  To report a case of granular cell tumor as a rare orbital pathology.
  
  
  METHODS
  A 50-year-old female presented with a 4-year history of diplopia, right ocular displacement and a firm nontender mass in her right lower lid. Computed tomography (CT) scan of the orbit disclosed a well-defined mass in the right inferior orbit involving the right inferior rectus. Subtotal excision of the mass was performed, and histopathologic and immunohistochemical studies revealed granular cell tumor. Subsequently, the tumor recurred and exenteration was required as multiple sessions of radiotherapy failed to prevent the residual tumor from growing.
  
  
  CONCLUSIONS
  Granular cell tumor, though very rare in the orbit, should be considered in patients with orbital masses especially in cases with involvement of the inferior rectus muscle. Infiltrative tumors may be impossible to completely resect and can rapidly recur following surgery.
authors.affiliation: Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Salour
authors.affiliation: Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Tavakoli
authors.affiliation: Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Karimi
authors.affiliation: Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mozhgan
authors.initials: M
authors.lastname: Rezaei Kanavi
authors.affiliation: Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Faghihi
keywords: Exenteration; Granular Cell Tumor; Orbit; Radiotherapy