5-azacytidine for the treatment of massive hepatosplenomegaly in a case of myelodysplastic/myeloproliferative neoplasm-unclassifiable

Myelodysplastic/Myeloproliferative Neoplasms (MDS/MPN) represent a distinct category of myeloid diseases in the World Health Organization classification, defined at diagnosis by clinical, morphologic and laboratory features which overlap both those of MDS and MPN. Within the “Overlap” MDS/MPN syndromes, MDS/MPN-Unclassifiable (MDS/MPN-U) is the least well characterized. MDS/MPN-U is a rare diagnosis, making up less than 5% of all myeloid disorders with no standard prognostic or treatment algorithms. 5-azacytidine is a standard treatment for MDS, but controversial results are available about its role for MDS/MPN-U and its effectiveness on extramedullary disease and hepatosplenomegaly. We reported the clinical management of a MDS/MPN-U patient characterized by massive hepatosplenomegaly with optimal response to 5-azacytidine.