title: A Case of Mature Natural Killer-Cell Neoplasm Manifesting Multiple Choroidal Lesions: Primary Intraocular Natural Killer-Cell Lymphoma.
abstract: OBJECTIVE
  Natural killer (NK) cell neoplasm is a rare disease that follows an acute course and has a poor prognosis. It usually emerges from the nose and appears in the ocular tissue as a metastasis. Herein, we describe a case of NK-cell neoplasm in which the eye was considered to be the primary organ.
  
  
  METHODS
  A 50-year-old female displayed bilateral anterior chamber cells, vitreous opacity, bullous retinal detachment, and multiple white choroidal mass lesions. Although malignant lymphoma or metastatic tumor was suspected, various systemic examinations failed to detect any positive results. A vitrectomy was performed OS; however, histocytological analyses from the vitreous sample showed no definite evidence of malignancy, and IL-10 concentration was low. Enlarged choroidal masses were fused together. Three weeks after the first visit, the patient suddenly developed an attack of fever, night sweat, and hepatic dysfunction, and 5 days later, she passed away due to multiple organ failure. Immunohistochemisty and in situ hybridization revealed the presence of atypical cells positive for CD3, CD56, and Epstein-Barr virus-encoded RNAs, resulting in the diagnosis of NK-cell neoplasm. With the characteristic clinical course, we concluded that this neoplasm was a primary intraocular NK-cell lymphoma.
  
  
  CONCLUSIONS
  This is the first report to describe primary intraocular NK-cell neoplasm. When we encounter atypical choroidal lesions, we should consider the possibility of NK-cell lymphoma, even though it is a rare disease.
authors.affiliation: Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tagawa
authors.affiliation: Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Namba
authors.affiliation: Department of Hematology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Reiki
authors.initials: R
authors.lastname: Ogasawara
authors.affiliation: Department of Department of Surgical Pathology, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kanno
authors.affiliation: Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Ishida
keywords: CD56; Choroidal tumor; Epstein-Barr virus; Natural killer-cell neoplasm; Primary intraocular lymphoma