De novo Philadelphia chromosome positive myelodysplastic syndrome: Report of two cases with brief literature review

Myelodysplastic syndromes (MDSs) are characteristically defined by the presence of specific karyotypic abnormalities, based on which they have been prognosticated. Translocation t(9;22)(q34;q11.2) (Philadelphia positive [Ph +ve]) and corresponding BCR-ABL fusion transcript is the defining parameter of chronic myeloid leukemia. It is also seen in a fair proportion of adult acute lymphoblastic leukemia. Occurrence of a Ph +ve MDS is very uncommon, and that too is seen mostly on progression to higher stage/acute leukemia. Even rarer is the de novo presence of Ph positivity in an MDS. A literature search through PubMed has shown only about forty cases of Ph +ve MDS among which less than half had shown Ph positivity at the time of initial diagnosis. Due to its rarity, this entity has not yet found its space in current WHO 2008 classification and is still under "yet to be validated phase" in current practice of hematological malignancies. The benefit of using a tyrosine kinase inhibitor in such a situation is also debatable. We report here two such cases of de novo Ph +ve MDS, diagnosed in last 1 1/2 year at our institute along with brief literature review.