The sample is a piece of bone marrow, with increased fibrosis. In the acute phase hyperplasia of all myeloid cell-lines (erythroblasts, megakaryocytes and granulocytes) is found. In places megakaryocytes are found in groups (arrows). With reticulin-staining, the increase of reticulin-fibers can be pin-pointed. There is also adipose tissue in bone marrow. 40x magnification, HE-staining.