Primary bone natural killer/T cell lymphoma, nasal type without EBV infection: a case report.

Primary bone NK/T cell lymphoma is very rare. We report a case of 52-year-old man of primary bone NK/T cell lymphoma and then progressed to NK leukemia. The patient had low-grade fever for 4-month, and Ultrasonic B revealed a diffuse hepatosplenomegaly without lymphadenopathy. PET scanning showed increased FDG uptake in many bones of the whole body. The diagnosis was established by bone specimen. These neoplastic cells demonstrated a typical immunophenotype of CD56, CD3, CD2 and MPO positive, and CD5, CD20, CD30, PAX-5, CD4 and CD8 negative. Primary bone ENKTL is very rare; it should be made with the combination of clinical feature, PET-CT image, and pathological characteristics, and should be distinguished from other lymphomas or leukemia involved in bone.