Primary extranodal nasal-type natural killer/T-cell lymphoma of the brain: a case report.

Natural killer (NK)/T-cell lymphomas represent a rare type of lymphoma derived from either activated NK cells or, rarely, cytotoxic T cells. These lesions are most commonly extranodal and tend to present as destructive lesions within the midline facial structures. Other than the nasal cavity and paranasal sinuses, several other extranodal sites of involvement have been reported, including the pharynx, gastrointestinal tract, and testis. Although secondary involvement of the central nervous system has been reported, a convincing case of primary brain NK/T-cell lymphoma has not been previously reported. Here, we report a case of primary brain lymphoma of NK/T-cell type with a characteristic phenotype expressing CD3epsilon, CD56, granzyme B, Epstein-Barr virus-encoded small nuclear RNAs, with germline T-cell receptor gene configuration, and showing an unusual intravascular component. The patient underwent extensive imaging studies, revealing only the brain lesion. The lymphoma failed to respond to therapy and the patient eventually died after transfer to a hospice facility. This unusual case highlights an unusual presentation of a rare disease entity and highlights the need for a better understanding of the biology and treatment of T-cell lymphomas.