The bone marrow is hypocellular for age with evidence of severe fibrosis and osteosclerosis The bone marrow is hypocellular for age with evidence of severe fibrosis and osteosclerosis
Other areas are more cellular and contain an increased number of atypical megakaryocytesOther areas are more cellular and contain an increased number of atypical megakaryocytes
A high-power image shows a marked megakaryocytic proliferation with abnormal-appearing megakaryocytes, micromegakaryocytes and megakaryoblasts. Normal maturing hematopoiesis is virtually absent.A high-power image shows a marked megakaryocytic proliferation with abnormal-appearing megakaryocytes, micromegakaryocytes and megakaryoblasts. Normal maturing hematopoiesis is virtually absent.
Immunohistochemistry for CD42b highlights sheets of abnormal megakaryocytesImmunohistochemistry for CD42b highlights sheets of abnormal megakaryocytes
Immunohistochemistry for CD61 shows increased number of megakaryocytes and megakaryoblastsImmunohistochemistry for CD61 shows increased number of megakaryocytes and megakaryoblasts
Circulating megakaryoblasts are noted in peripheral bloodCirculating megakaryoblasts are noted in peripheral blood