Pulmonary fibrosis with megakaryocytoid cell infiltration and chronic myelogenous leukemia

The relationship between fibrosis and megakaryocytic infiltration in the lungs of patients with Philadelphia-chromosome (Ph1)-positive chronic myelogenous leukemia (CML) is the focus of this review. Ph1-positive megakaryocytes are thought to reach and accumulate in the pulmonary vasculature through the marrow-blood barrier. In 21 autopsied patients with accelerated phase or blastic crisis of CML, megakaryocytic infiltration to the lungs was demonstrated in 10 patients, myelofibrosis in 12 patients and both in 5 patients. In 2 of the 10 patients with increased megakaryocytes in the lungs, relatively new fibrosis and alveolar damage in the acute phase were demonstrated with the simultaneous occurrence of myelofibrosis-"myelopulmonary fibrosis."Leakage of mitogenic factors resulting from an abnormality in the packaging mechanism of alpha-granules in these cells termed acquired grey platelet syndrome could cause fibrosis in the lungs as well as the bone marrow.