Myeloproliferative disorders with selective differentiation toward megakaryocytic cells. A clinicopathological study of three autopsy cases.

Three autopsy cases of myeloproliferative disorders with selective differentiation toward megakaryocytic cells were reported with a clinicopathological analysis. All of these cases had some common distinctive features; (1) patients, adult of more than 40 years of age, (2) relatively acute fatal course (about 20 to 100 days), (3) continued pancytopenia in the peripheral blood, (4) so-called blast cells, occasionally showing accumulation, according to the length of total duration, in addition to overwhelming predominance of atypical megakaryocytic cells in the bone marrow, and (5) an increased tendency of fibrillosis in the interstitium of the bone marrow corresponding to the more or less prolonged duration of the course. From these facts, they should be compatible with so-called megakaryocytic myelosis. Some relationship between this disorder and myelogenous leukemia, and infiltrative tendency of megakaryocytic cells in the extramedullary organs had also been discussed shortly.