title: Unusual orbital lymphoma undetectable by magnetic resonance imaging: a case report.
abstract: BACKGROUND
  We report the case of a patient with orbital malignant lymphoma that was not detected by imaging studies when she presented with impaired vision, which lead to her eventual loss of sight.
  
  
  METHODS
  A 71-year-old Japanese woman complained of deteriorating vision in her left eye. On examination, papilledema was detected, but magnetic resonance imaging only showed slight thickening and enhancement of the left optic nerve. A diagnosis of idiopathic optic neuritis was made and corticosteroid pulse therapy was administered. During the next four months, the patient received a total of four courses of corticosteroid pulse therapy, but she still suffered from bilateral loss of vision. A second magnetic resonance imaging procedure revealed tumors in both orbits and a biopsy showed diffuse large B-cell malignant lymphoma.
  
  
  CONCLUSIONS
  The possibility of malignant lymphoma should be considered in patients with recurrent optic neuropathy despite administration of corticosteroid pulse therapy, even when there are no abnormalities on cerebrospinal fluid examination or magnetic resonance imaging.
authors: Department of Ophthalmology, Hiroshima Prefectural Hospital, Hiroshima, Japan, 1-5-54, Ujinakanda, Minami-ku, Hiroshima 734-8530, Japan.
authors: Maria
authors: M
authors: Tatsugawa
authors: Hidetaka
authors: H
authors: Noma
authors: Tatsuya
authors: T
authors: Mimura
authors: Hideharu
authors: H
authors: Funatsu