[A histopathological study of bone marrow following chemotherapy of acute myeloid leukemia]

The findings of serial observation on 128 bone marrow biopsies following the completion of remission-induction chemotherapy from 12 patients with acute myeloid leukemia (AML), suggest that chemotherapy gave rise to various histologic changes, including hypoplasia, oedematous marrow stroma with widely dilated sinuses and large unilocular fat cells, ('structured fat') developed from multilocular preadipocyte. Early regenerating hemopoietic foci of erythroid, granulocytic and megakaryocytic cells were almost exclusively in the areas of structured fat. Our data showed that fat cells may play an important role in hemopoietic regeneration. and that chemotherapy does not eradicate leukemic cells even in those cases with clinically complete remission. If biopsy specimen showed abnormal localization of immature precursors, (ALIP) It would indicate that complete remission is not reached. and the Patients must receive consolidation chemotherapy until 'ALIP' clusters disappear.