Prognostic significance of bone marrow reticulin fibres in idiopathic myelofibrosis: evaluation of clinicopathological parameters in a scoring system.

A clinicopathological scoring system was performed for obtaining a better estimate of prognosis in 50 patients with idiopathic myelofibrosis (IMF). Laboratory parameters including Hb-level, leukocyte and platelet counts, percentage of blast cells in peripheral blood, spleen and liver size, and a semiquantitative histological grading of reticulin fibre content of bone marrow biopsies taken at the time of initial diagnosis were analysed. Based upon these haematological and histological parameters three prognostic groups could be categorized with a significantly different survival (low-risk group with 21 patients = 75 months; medium-risk group with 18 patients = 51 months, and 11 patients in a high-risk group = 18 months). In an univariate (log rank test) and in a multivariate regression analysis the Hb-concentration, mild splenomegaly (less than 5 cm) and a higher grade of bone marrow reticulin content proved to be important prognostic parameters, whilst leukopenia, thrombocytopenia and the presence of peripheral blast cells were only of prognostic significance within the first 6 months from initial diagnosis. It was concluded that the increase of reticulin fibre deposition in bone marrow together with anaemia and mild splenomegaly could be responsible for a progressively worse life-expectancy of high-risk patients with idiopathic myelofibrosis.