Quiescent nasal T/NK cell lymphoma manifested as primary central nervous system lymphoma

A 57-year-old man was diagnosed as primary T/NK-cell central nervous system lymphoma (CNSL) with intraocular involvement. However, review of a surgica l specimen taken three years before for chronic paranasal sinusitis reveale d an overlooked nasal T/NK cell lymphoma (TNKL), which showed similar histo morphology and immunophenotype with the CNS disease, Another patient, a 43- year-old woman, was initially diagnosed as a rare primary leptomeningeal T- cell lymphoma with ocular manifestation, Three years later, an isolated nas al TNKL emerged. Immunohistochemical and cytogenetic studies confirmed the same nature of the CNSL and the nasal TNKL, The nasal TNKLs of both patient s had a strong expression of CD3, CD56, and Epstein-Barr virus antigens, bu t features of angiodestruction and mucosal ulceration were absent, We propo se that: 1. a locally silent "quiescent" form of nasal TNKL may exist; and 2. a thorough examination and even blind biopsy of the nasal cavity is indi cated when primary T/NK-cell CNSL is diagnosed. (C) 1999 Wiley-Liss, Inc.