Abstract
Members of the French-American-British Cooperative Leukemia Working Group met to review cases of aplastic anemia, hypocellular myelodysplastic syndrome and hypocellular acute myeloid leukemia. Criteria were proposed and modified following three workshops. Additional input was obtained from another hematopathologist with a special interest in bone marrow histology and immunohistochemistry. Guidelines were recommended based on the workshop results as well as additional studies including selective immunohistochemistry, flow cytometry and cytogenetics.