Myelodysplastic syndromes (MDS) are a group of heterogenous disorders of blood and of the haematopoeitic bone marrow which have been recently in the center of interest of both clinical haematologists and pathologists. The FAB classification is based on cytology; for histological assessment, a special histopathological classification appears to be more appropriate. The main histological findings in MDS and some ultrastructural changes are shown in 138 bone marrow biopsies from 81 patients with MDS. Histological examination brings some findings that cannot be obtained by cytology. Optimal samples well processed can give valuable information without need of special staining methods. The latter can complement the basic information with some additional data or compensate for some technical defects of the slides.

Hlavův 1 patologicko anatomický ústav 1 LF UK Praha