Concomitant Essential Thrombocythemia andMature B Lymphoproliferative Disorder in a Patient

A-64-year old male presented with cough, weight loss, and maculopapular rash for 15-20 days. on examination, he was found to have cervical lymphadenopathy and splenomegaly. his leukocyte count was 62.1x109/l, platelets were 1169x109/l and ldh was 816 iu/l. peripheral blood film showed a leukoerythroblastic picture with thrombocytosis. he was started on hydroxyurea and allopurinol. subsequently, bone marrow evaluation was done which depicted increased lymphoid cells with an m:e ratio of 4:1. cellular areas exhibited an increase in myeloid precursors along with prominent lymphoid cells and abundant megakaryocytes. immunohistochemistry showed an increase in b-lymphocytes. grade mf-2 reticulin fibrosis was noted. overall findings suggested essential thrombocythemia (et). on flow cytometry, cd45-positive lymphoid cells population was 31% and showed reactivity to pan-b-markers with lambda light chain restriction. janus kinase 2 (jak 2) mutation was detected while bcr-abl1 translocation was negative. a diagnosis of et progressing to myelofibrosis and mature b-lymphoproliferative disorder was made. hydroxyurea and allopurinol were stopped while ruxolitinib was introduced and 2.5 years later he remains stable on this treatment.