Bone marrow biopsy (BMB) in myelodysplastic syndrome (MDS) frequently reveals a slight alteration in the reticulin stroma which does not have any clinical significance. However, in a minority of cases, full-blown bone marrow fibrosis (BMF) can be found.

Primary MDS patients with BMF show distinct clinico-pathological features and an unfavourable prognosis mainly attributable to complications deriving from pancytopenia and continuous transfusions, while leukemic transformation occurs only rarely. Since BMF may characterize other hematological disorders, primary MDS with BMF should be included in the differential diagnosis particularly with malignant myelofibrosis (MM) and idiopathic myelofibrosis (IMF).

Secondary MDS with BMF represent a variety of preleukemic conditions in subjects treated for previous neoplasias. Unlike the primary forms, they do not form a clearcut clinico-pathological entity.