An update of 2000 guideline for management of this rare lymphoproliferative disorder. Key messages: important to achieve CR if possible. Purine analogue monotherapy (cladribine or pentostatin) mainstay of initial treatment (except HCL-V), with good CR rate. Rituximab and purine analogue combination for relapse. Important not to assess response too early (4-6 months post treatment trephine recommended with clusters of CD20+ cells indicative of residual disease). BRAF V600E mutation recently reported in 47/47 cases at time of guideline writing (see update section).

Declaration of Interests

The BSH paid the expenses incurred during the writing of this guidance. None of the authors had conflicts of interest to declare. All authors have made a declaration of interests to the BSH and Task Force Chairs which may be viewed on request.