Polycythaemia Vera and Myelofibrosis

Bone marrow biopsies were made in 63 patients with polycythaemia vera and in three patients with primary myelofibrosis having polycythaemic blood pictures. The histological findings in polycythaemia vera were classified as follows: normal bone marrow in 14, hyperplastic bone marrow in 17, hyperplastic bone marrow with increased reticulin fibers in 19, early myelofibrosis in 9 and advanced myelofibrosis in 4 patients. In 12 of the polycythaemic patients bone marrow biopsy was repeated after nine to 32 months. In eight patients the histological picture was unchanged, three showed progression of myelofibrosis, and in one fibrotic changes possibly due to a miselading biopsy specimen had disappeared. The histological findings were in good correlation with clinical parameters and in only three polycythaemia vera patients with early myelofibrosis in histological specimens no clinical or laboratory signs of myelofibrosis were detected. Myelofibrosis was more often encountered in patients with a long history of polycythaemia vera and at the time of the diagnosis of the disease patients with increase in reticulin fiber content and with myelofibrosis in marrow sections had shown slightly more often leukocytosis, circulating normoblasts and splenomegaly than the other patients. The reliability of bone biopsy from the iliac crest and its value in polycythaemia vera are evaluated. The relationship between polycythaemia vera and myelofibrosis is discussed in the light of the concept of myeloproliferative diseases.