RESUMO
Acute megakarioblastic leukemia (AMKL) is a rare myeloproliferative syndrome with a fulminant clinical course characterized by progressive pancytopenia, palior, weakness and severe haemorrhage. Two cases of AMKL are presented: a 18-year old male with pancytopenia and massive haemorrhage, lymphadenopathy, organomegaly and mediastinal tumour. The diagnosis of AMKL was established by cytological and immunocytochemical analyses of peripherial blood cells (blasts were GPIIIa and GPIb postitive), by histological analysis or the bone marrow and lymph node, and immunohistochemical analysis of lymph node. The second case had megakarioblastic transformation of HGL which was confirmed by cytomorphological and immunophenotypical analyses. In spite of therapy, the patients died soon after the first signs of the disease.