Myelodysplastic syndromes: analysis of morphological features related to the FAB-classification.

In a retrospective study of 96 patients with a myelodysplastic syndrome, the reproducibility of the French-American-British (FAB) classification was determined. Morphological abnormalities in peripheral blood and bone marrow were studied. Slides were reviewed by 3 examiners. All 3 observers agreed on morphological classification in 61% of cases, pairs of 2 in 64, 76 and 76%. The final diagnosis was refractory anaemia (RA) in 7 patients, acquired sideroblastic anaemia (AISA) in 2, chronic myelomonocytic leukaemia (CMML) in 31, refractory anaemia with excess of blasts (RAEB) in 34 and RAEB in transformation (RAEB-t) in 22. Dyserythropoiesis, dysgranulopoiesis and dysmegakaryopoiesis were found in all FAB subgroups. Dyserythropoiesis was significantly more frequently encountered in RAEB than in RAEB-t and CMML.