Hairy cell leukemia: lessons learned in twenty-five years.

This review was written to highlight the lessons learned in HCL in the past 25 years. It should serve as a guideline to practicing hematologists and oncologists regarding the diagnosis and management of HCL patients. It should stimulate investigators in training to realize that a disease can be understood with time; however, additional clinical observations and laboratory experiments may help to improve the survival rate even more.