Reliability and limitations of cytochemistry in diagnosis of acute myeloid leukemia. Minireview.

Accurate characterization of leukemic blast cells is an important prerequisite of the precise diagnosis of acute myeloid leukemia and has a great impact on therapy and prognosis. The purpose of this review is to consider the present possibilities and limitations of enzyme cytochemistry and to emphasize how cytochemistry may contribute to the final classification and differential diagnosis of acute myeloid leukemia. The role of conventional enzyme cytochemistry, either dominant or subsidiary, in the discrimination of acute myeloid leukemia subgroups is discussed. The survey confirms the necessity of immunological marker analysis in the accurate diagnosis of minimally differentiated myeloid leukemias and acute leukemia of megakaryocytic lineage. In these cases, the cytochemical evaluation provides insufficiently relevant information regarding blast cell origin. On the other hand, cytochemical investigation is appreciated to be dominant over immunophenotyping in characterizing majority of acute myeloid leukemia subgroups, because of the availability of standardized and sufficiently specific cytochemical reactions and, because of the lack of specificity of the many of immunological markers against myeloid antigens. The immunocytochemical, cytogenetic, molecular biology and electron microscopic studies shortly mentioned in this review supplement the information for correct diagnosis of acute myeloid leukemia.