[Some difficult problems in the classification of acute leukemia]

The authors presented 5 cases of ANLL and 6 cases of ALL according to FAB classification and further classified them with leukemic cell morphology, cytochemistry and immunophenotyping. Five cases of them belonged to low grade peroxidase ANLL (LP-ANLL), 4 to hybrid acute leukemia (HAL) and 2 to acute undifferentiated leukemia (AUL). The importance of immunophenotyping of leukemic cells in classification of acute leukemia was emphasized and the criteria for diagnosis of LP-ANLL, HAL and AUL discussed. The authors are of the opinion that the diagnosis of these three kinds of acute leukemia is difficult and the prognosis is serious.