Histiocytic/dendritic cell transformation of indolent B-cell neoplasms: Clinical laboratory evidence of lineage conversion in hematolymphoid malignancies

It is well known that pluripotent progenitors of normal hematopoietic cells can differentiate into cell lineages that are distinct in morphology, immunophenotype and biological function [1]. The conventional concept holds that once a hematopoietic progenitor is committed to a given lineage, its fate is sealed and irreversible. This phenomenon of lineage commitment has also been universally observed in hematolymphoid neoplasms in the past.