[Extramedullary blastic transformation revealed by a prolonged fever during the course of a 5q- syndrome].

Introduction: Fever during a myelodysplastic syndrome can be due to infectious complications, systemic disease or acute transformation with clonal evolution.

Case Report: A 51-year-old woman, with a 5q- syndrome and neutropenia, presented with a several week fever duration. Infectious work-up was negative and therapy with antibiotics had no influence on the clinical course. Neither bone marrow nor blood blasts were detected, but liver biopsy demonstrated significant blast infiltration compatible with the diagnosis of acute myeloid leukaemia (AML).

Conclusion: The absence of blasts in blood or bone marrow does not exclude the malignant transformation of a myelodysplastic syndrome to AML. Tissue biopsy may be necessary to confirm the leukaemic progression.