title: Extranodal right-optic nerve Rosai-Dorfman disease: A rare localization case report.
abstract: BACKGROUND
  Rosai-Dorfman is a rare disease that usually occurs in young adults. It is characterized with massive painless cervical lymphadenopathy and histiocyte proliferation. Isolated intracranial involvement is extremely rare. Our aim is to present a new rare case of extranodal Rosai-Dorfman disease that involved the right optic nerve in a 4-year-old boy.
  
  
  METHODS
  A 4-year-old boy with right-sided convergent strabismus and amblyopia lasting for 1 year was treated at the Department of pediatric ophthalmology. Initial optical fundus examination was normal. Examination repeated after 1 year noted the atrophy of the optic nerve papilla. Visual evoked potentials of the right eye showed normal findings of prechiasmatic visual pathway with severe dysfunction of the right optic nerve. Magnetic resonance imaging (MRI) of the brain and orbits showed expansive changed and elongated right optic nerve with contrast enhancement, and smaller lesion in the right temporal operculum region visible in T2 and fluid-attenuated inversion recovery sequence. Through small eyebrow "keyhole" osteoplastic frontoorbital craniotomy the fusiform enlarged (to 2 cm) right optic nerve was identified, resected between the eyeball and optic chiasm, and transferred for pathohistological analysis. Early postoperative course had no complications. Histological, immunohistochemical, and ultrastructural analyses revealed extranodal Rosai-Dorfman disease. Right periorbital edema was verified on the 7thpostoperative day and regressed to supportive therapy. Control multi slice computed tomography (MSCT) and MRI of endocranium and orbits showed total tumor removal with no signs of complications.
  
  
  CONCLUSIONS
  Although rare, extranodular intracranial Rosai-Dorfman disease should be taken into account in the differential diagnosis of intracranial and intraorbital lesions, especially in the pediatric age group.
authors.affiliation: Department of Neurosurgery, University Hospital Center Zagreb, School of Medicine, Zagreb, Croatia.
authors.forename: Jakob
authors.initials: J
authors.lastname: Nemir
authors.affiliation: Department of Neurosurgery, University Hospital Center Zagreb, School of Medicine, Zagreb, Croatia; Department of Neurosurgery, Dubrovnik General Hospital, Dubrovnik, Croatia.
authors.forename: Ines
authors.initials: I
authors.lastname: Trninic
authors.affiliation: Department of Neurosurgery, University Hospital Center Zagreb, School of Medicine, Zagreb, Croatia.
authors.forename: Kresimir S
authors.initials: KS
authors.lastname: Duric
authors.affiliation: Department of Pathology, University Hospital Center Zagreb, School of Medicine, Zagreb, Croatia.
authors.forename: Antonia
authors.initials: A
authors.lastname: Jakovcevic
authors.affiliation: Department of Neurosurgery, University Hospital Center Zagreb, School of Medicine, Zagreb, Croatia.
authors.forename: Goran
authors.initials: G
authors.lastname: Mrak
authors.affiliation: Department of Neurosurgery, University Hospital Center Zagreb, School of Medicine, Zagreb, Croatia.
authors.forename: Josip
authors.initials: J
authors.lastname: Paladino
keywords: Extranodal; Rosai–Dorfman disease; optic nerve; pediatric tumor