[Nosology of myeloproliferative disorders]

A nosological description of the myeloproliferative diseases has to demonstrate the characterizing features of the various entities as well as their common characteristics and peculiarities. Here it becomes evident that one must differentiate between diseases with neoplastic proliferation of above all one series of cells (pure cell proliferation) and such one with two or more series of cells (mixed cell proliferation). Transitions from pure cell forms to mixed cell forms and change of the prevailing cell series in mixed cell proliferations, respectively, may be expected like certain terminal results (blastic transformation, myelofibrosis). The proposition of an improved classification demands a correct cytological, cytochemical and histological investigation of the bone marrow as well as repeated analyses of the course.