Complete remission of hairy cell leukemia variant (HCL-v) complicated by red cell aplasia post treatment with rituximab

Hairy cell leukemia variant (HCL-v) is a rare form of a chronic B cell lymphoproliferative disorder. Unlike typical hairy cell leukemia (HCL) where the complete response (CR) rate to 2-chlorodeoxyadenosine and 2'-deoxycoformycin can approach to about 90%, in HCL-v CR is rare and partial response (PR) occurs in approximately 50% with these agents. Rituximab treatment in relapsed or refractory HCL results in a CR of 13% to 53%, but its use in HCL-v has not been reported in the literature to our knowledge. We describe a patient with HCL-v, whose course was previously complicated by pure red cell aplasia who achieved CR after treatment with rituximab, and briefly review outcomes of treatments used in HCL-v in the current literature.