[Lineage assignment in acute leukemia: confrontation between cytology and immunophenotyping]

Abstract

Objective: The determination of the cellular lineage in acute leukemia is a crucial step in the diagnosis and the later therapeutic conduct. In Tunisia, emerging country, some cases of acute leukemias are still treated on the basis of an only cytologic study because of lack of cytometry. Our objective is to realize a confrontation between cytology and flow cytometry in the diagnosis of AL and to analyze discrepancies.

Patients and methods: The study concerns 100 cases of AL. A second double-blind examination of the bone marrow smears of acute leukemias is realized by two cytologists and confronted to immunophenotyping.

Results: In two cases of AML, flow cytometry reassigned lineage into T ALL and biphenotypic AL. In three cases of ALL the lineage was reassigned into undifferentiated acute leukemia (2 cases) and biphenotypic acute leukemia (1 case). Lineage was not established in four cases, immunophenotyping allowed the diagnosis of B ALL in 3 cases, and of biphenotypic acute leukemia in 1 case. In both cases of discrepant findings, flow cytometry allowed the diagnosis of biphenotypic acute leukemia in a case and of AML in the other one.

Conclusion: The cytological study remains insufficient in the diagnosis of lineage even with experimented cytologists. Immunophenotyping is essential in lineage assignment and reassignment.

Keywords: Acute leukemia; Cytologie; Cytology; Immunophenotype; Immunophénotypage; Leucémie aiguë.