Bone marrow histology in myelodysplastic syndromes. I. Histological findings in myelodysplastic syndromes and comparison with bone marrow smears.

Forty bone-marrow trephine biopsies of patients with myelodysplastic syndromes (MDS) were studied and compared with bone marrow smears. It proved possible to make the diagnosis of MDS on the basis of bone-marrow biopsies. Features of abnormal erythropoiesis and myelopoiesis, although different from those observed in smears, were easily detectable. Moreover, obvious advantages of bone-marrow biopsy over bone-marrow smears were found. Firstly, the biopsy in MDS gives an exact assessment of the cellularity; secondly, the presence of reticulin fibres, increased in the majority of the cases, can be evaluated; thirdly, dysmegakaryopoiesis is more easily detected in trephine biopsies than in smears; finally, abnormal behaviour of myeloblasts, clustering centrally in the bone marrow, is frequently observed before the smears show an excess of myeloblasts. The bone-marrow biopsy also has a role in difficult cases, where the diagnosis of MDS can not be established on just bone-marrow smears. The five types of MDS, as described by the FAB group, do not represent recognizable histological entities.