Fibrosis of the bone marrow may be present in various hematologic diseases such as myeloproliferative diseases (MPD) and acute myeloid leukemias (AML). In primary myelodysplastic syndromes (MDS) myelofibrosis is a relatively rare event. Patients affected by MDS with myelofibrosis (H-MDS) present intriguing features that give rise to the hypothesis that H-MDS might represent a new entity. The purpose of this concise review is to summarize the contrasting opinions of the authors who have described some series of H-MDS patients. Many characteristics induce one to distinguish H-MDS from classical MDS, so that the former has been considered each time as a transitional stage between MDS and MPD, an acute transformation of an MPD, or an AML from the beginning. The pathogenetic mechanism of the fibrosis of the bone marrow may be similar to sic sic of the MPD in which a stimulus to secrete reticuline or collagen derives from abnormal marrow megakaryocytes. Importance of karyotype abnormalities are discussed. Clinical features of the syndrome are rather heterogeneous; evaluation of the survival of the described single cases reveals that mean survival is not significantly different from classical MDS. Finally, trephine biopsy and the cytogenetic study are necessary to permit the diagnosis of H-MDS. However, because of the relatively low number of cases, series of patients are necessary to correctly classify this syndrome.

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