Leukemoid reactions in hematological malignancies : report of three cases and review of the literature

Abstract EN

Leukemoid reactions (LR) are important differential diagnoses in hematologieal malignaneies as they may be misinterpreted as a relapse or a seeond leukemia.

We report 3 pediatrie cases including one non-Hodgkin's lymphoma and two acute lymphoblastic leukemias (ALL).

One LR resembled chron-ic myeloid leukemia (CML) and two LR's suggested that a relapse of ALL had occurred, which has major clinical implications.

Two of the patients had the LR on more than one occasion (total 6 episodes).

CML or relapse were excluded mainly on clinical grounds, by normal bone marrow stud-ies, and in the case of CML by a high score of leukocyte alkaline phosphatase (LAP).

No infections could be detected during the episodes of LR.

We reviewed the literature looking for LR's reported during the course of hematological malignancies, and could find very few reports of such cases.

We believe the LR's in our cases are due to rebound effects following neutropenia, and possibly due to prednisolone in one episode.

We conclude that LR's are possible during the course of hematological malignancies.

This possibility should be borne in mind after excluding important differential diagnoses, like infections.

The importance of recognizing LR's in hematological malignancies is to avoid a misdiagnosis of a relapse or a second malignancy.