Acute agranular CD4-positive natural killer cell leukemia. Comprehensive clinicopathologic studies including virologic and in vitro culture with inducing agents

Abstract

A case of clonal acute natural killer (NK) cell leukemia with an unusual morphology (agranular) and unique phenotype (CD3-, CD56+, CD4+, CD15+) is presented. Unlike as in other acute NK leukemias, EBV was negative; there was no evidence of HHV-6. The tumor cell, after culturing with differentiating agents, may have been induced to express a T-cell immunophenotype.