Rapid progression of Myelodysplastic syndrome to acute myeloid leukemia on sequential azathioprine, IFN-beta and copolymer-1 in a patient with multiple sclerosis.

A woman with relapsing-remitting multiple sclerosis (MS) was treated with oral azathioprine (AZA) for 4 years and subsequently switched to interferon-beta1a. Five years later, leukopenia developed and resolved after interferon was discontinued; MS treatment was changed to copolymer-1. Recurrent pancytopenia subsequently led to diagnosis of myelodysplastic syndrome (MDS) with deletion of the long arm of chromosome 5 (MDS 5q-). Within several months, unusually rapid for this subtype, MDS progressed to secondary acute myeloid leukemia. While AZA is the probable cause for the chromosomal deletion and MDS, combined or sequential immunomodulatory therapies may permit clonal expansion of malignant hematopoietic progenitors. Copyright 2006 S. Karger AG, Basel.