Follow-up studies with sequential bone marrow biopsies in chronic myeloid leukaemia and so-called primary (idiopathic) osteo-myelofibrosis. Evolution of histopathological lesions and clinical course in 40 patients.

A clinicopathological follow-up study was performed on 17 patients with chronic myeloid leukaemia (CML) and 23 cases with so-called primary (idiopathic) osteo-/myelofibrosis (OMF) concentrating on a comparison between clinical data and multiple sequential biopsies of the bone marrow. Histological classification of bone marrow lesions was done according to the subtypes proposed by Georgii et al. At clinical diagnosis initial trephine biopsies in CML showed in only 6/17 cases a pronounced granulocytic proliferation or CGL. In 9/23 patients with OMF a so-called hyperplastic or early hypercellular stage was encountered with a mixed megakaryocytic-granulocytic pattern without or with minimal reticulin fibres (CMGM/EMS). The histopathology of this early stage OMF as well as the later evolving advanced fibrosclerotic lesions (AMS/OMS) were by morphological aspects alone not distinguishable from cases with CML showing prominent fibrosclerotic alterations. At presentation 5/17 patients with CML displayed already some degree of reticulin fibre formation (EMS). Following serial trephine biopsies in CML with an increased megakaryocyte proliferation (CMGM), a remarkable tendency for myelofibrosis was present. The dynamics of this fibrosclerotic transformation seem to be variable in CML and OMF likewise. However, they are related to abnormal megakaryopoiesis as well as to duration respectively progress of disease, paralleled by corresponding haematological parameters. This longitudinal case control study emphasizes that histopathology of the bone marrow taken at clinical diagnosis may reflect different stages of chronic myeloproliferative diseases and therefore should be always accompanied by relevant clinical and cytogenetic findings to enable a correct diagnosis.