Mast cells and myelofibrosis.

Autopsy of a patient with well-documented myelofibrosis revealed marked proliferation of mast cells associated with areas of bone-marrow and splenic fibrosis. The findings suggest that the local fibrosis represents the healed phase of an inflammatory reaction mediated by mast cells via the release of histamine into the tissue spaces. Tissue mastocytosis may be the pathogenetic mechanism in some cases of myelofibrosis.