Nasal-type Natural Killer/T-cell Lymphoma of the Orbit

ABSTRACT

PURPOSE: To report two cases of nasal type Natural Killer (NK)/T-cell lymphoma of the orbit. METHODS: (Case 1) A 42-year-old woman presented with a 3-month history of painful proptosis and eyelid swelling in the right eye. Under the diagnosis of inflammatory pseudotumor, she was treated with intravenous and oral steroids. She visited our clinic with a 3-day history of proptosis with decreased visual acuity. Computed tomography (CT) revealed a large infiltrative mass in the right orbit. Incisional biopsy was performed in the right lower lid. (Case 2) A 42-year-old man was referred for consultation with a 1-month history of fever of unknown origin. Two months previously uveitis had developed in the right eye and had been treated with topical steroid. CT revealed an infiltrative soft-tissue like mass in the left orbit. Incisional biopsy was performed in the orbital area. RESULTS: Histopathologically, a diffuse infiltration of atypical lymphocytes was observed with angiocentric pattern in both patients. The infiltrating cells were positive on immunohistochemical stains for CD3 and CD56. The tumor cells were negative for CD20 and CD30. In situ hybridization demonstrated Epstein-Barr virus-encoded nuclear RNA. A diagnosis was made with NK/T-cell lymphoma of nasal type associated with Epstein-Barr virus infection. CONCLUSIONS: NK/T-cell lymphoma of the orbit is rare and has poor prognosis. It is important to distinguish a NK/T-cell lymphoma from the pseudotumor or uveitis unresponsive to steroid therapy.