Cutaneous intravascular natural killer-cell lymphoma: a case report and review of the literature.

OBJECTIVES: To our knowledge, since 2003, there have been 11 reported cases of intravascular natural killer (NK)-cell lymphoma (IVNKL). Herein we describe the 12th case.
METHODS: H&E and Envision immunohistochemical stains as well as in situ hybridization were used to study this disease in combination with review of the literature.
RESULTS: Half of the cases reported to date are from China and Taipei. The clinical manifestation of IVNKL is erythema in the limbs and trunk, although patients' conditions have varied notably from each other. One-year survival rate is about 40%.
CONCLUSIONS: IVNKL should be distinguished from extranodal NK/T-cell lymphoma (nasal type) and aggressive NK-cell leukemia. These three diseases have a similar phenotype and are all related to Epstein-Barr virus infection. However, the pathogenesis of similarities and differences needs further study. In particular, IVNKL is quite unusual. The treatment of IVNKL is difficult, and the prognosis is poor. Currently, IVNKL is not included in the World Health Organization classification subtypes and has been classified into NK/T-cell lymphoma (nasal type). However, in view of the unique characteristics of this disease, we propose that the diagnosis be independent, since this will facilitate further study of this disease. Copyright© by the American Society for Clinical Pathology.