[Diagnosis of chronic myeloproliferative diseases based on bone marrow biopsy]

The bone marrow biopsies and laboratory data of 248 patients with untreated chronic myeloproliferative disorders have been evaluated according to the Hannover Classification. 47.6 per cent of the cases were classed as primary or basic diseases, including chronic myeloid leukaemia common type, chronic myeloid leukaemia megakaryocytic type, chronic megakaryocytic-granulocytic myelosis, polycythaemia vera and essential thrombocythaemia. In 52.4 per cent of the biopsies the advanced stages of the primary diseases like increase of fibers and loss of differentiation were noted; the increase of fibers in myeloid leukaemia megakaryocytic type and in chronic megakaryocytic-granulocytic myelosis, and loss of differentiation in chronic myeloid leukaemia common type were frequently noted. In 14.1 per cent of the cases the advanced myelofibrosis and blast cell accumulations obscured the histological features of the primary disease, therefore these cases were placed in the unclassifiable group. The cases without increase of fibers and loss of differentiation accounted for only 4 per cent of the unclassifiable category. Leucocyte and platelet count as well as haematocrit values showed considerable overlapping and scattering and were generally lower in cases which developed myelofibrosis.