Acute megakaryocytic leukaemia (AML-M7) with myelofibrosis terminating in AML-MO with concurrent liver fibrosis

Bridging necrosis and reticulin bridging fibrosis induced by intrahepatic involvement of acute biphenotypic leukemia

A 47-year-old Japanese woman was diagnosed as having acute biphenotypic leukemia with association of t(9;22)(q34;q11). Cholestatic liver dysfunction arose, and she died of cachexia and intracranial hemorrhage. Autopsy showed unusual hepatic fibrosis. In the liver, bridging infiltration, bridging necrosis and bridging fibrosis by leukemic cells were seen. It seemed that the degree of fibrosis was associated with the number of aggregates of infiltrating leukemic cells. The fibrotic foci were predominantly composed of reticulin and collagen fibers, and distortion of the lobules was observed. Immunohistochemically, dense bundles of alpha-smooth muscle actin (ASMA)-positive stromal cells, namely activated hepatic stellate cells (HSCs), were observed in the immature fibrotic foci as well as along the sinusoids densely infiltrated by leukemic cells. No cells positive for TGF-beta1 or PDGF-BB were identified. In conclusion, extensive intrahepatic involvement by neoplastic cells in adult acute biphenotypic leukemia may cause the unusual "disorganized" hepatic fibrosis.

Granulocytic sarcoma of megakaryoblastic differentiation in the lymph nodes terminating as acute megakaryoblastic leukemia in a case of chronic idiopathic myelofibrosis persisting for 16 years

A 43-yr-old Japanese woman presented with mild anemia, leukocytosis and splenomegaly in May 1984. Splenomegaly and anemia gradually progressed. Sixteen years later, in October 2000, she developed inguinal lymphadenopathy. Biopsy of the lymph node revealed infiltration of blasts, megakaryocytes, fibroblasts and myeloid cells. Large blasts with basophilic cytoplasm with cytoplasmic projections appeared in the peripheral blood. These blasts were negative in peroxidase stain, positive in acid phosphatase and weakly positive in periodic acid-Schiff stain. Immunohistochemical staining with monoclonal antibodies revealed that these blasts were positive with anti-CD41 (glycoprotein IIb/IIIa) and negative with other monoclonal antibodies. So diagnosis of granulocytic sarcoma in megakaryoblastic transformation from chronic idiopathic myelofibrosis was made. A cytogenetic study revealed that bone marrow cells were 46,XX del(13)(q?) initially and additional abnormalities including der(5,5,11)(q11;q13)ins(5;?)(q11;?) were found when she developed megakaryoblastic transformation. Granulocytic sarcoma of megakaryoblastic transformation from chronic idiopathic myelofibrosis is a rare event. Immunophenotyping with monoclonal antibody for CD41(glycoprotein IIb/IIIa) confirmed the diagnosis.