Nasal and nasal type CD56+ natural killer cell/T-cell lymphoma: a case with rapid progression to bone marrow involvement.

We describe herein a case of CD56+ natural killer cell lymphoma (NKCL) that showed unusual clinical manifestations and a fulminant course of disease. A 70-year-old male patient presented with rapidly growing skin lesions and fever; a nasal lymphoma was subsequently detected and bone marrow involvement developed within a few weeks. Although the time relationship is not clear, bone marrow involvement could be dissemination from localized disease of nasal and nasal type NKCL. As seen in our case, the course can be excessively aggressive and fulminant even when it first appeared as a localized disease, and CD56 positivity, which is a specific characteristic of NKCL, may serve as a factor showing a poor prognosis for a malignant lymphoma.