A rare acute leukemia of ambiguous lineage characterized by clonal proliferation of primitive hematopoietic cells, primarily in the bone marrow and blood, lacking lineage-specific markers and detectable genotypic alterations. The patients present with leukocytosis, anemia, variable platelet count and a variety of nonspecific symptoms related to ineffective hematopoesis (fatigue, bleeding and bruising, recurrent infections, bone pain) and/or extramedullary site involvement (lymphadenopathy, splenomegaly, hepatomegaly).

Encephalopathy is a term that means brain disease, damage, or malfunction. In general, encephalopathy is manifested by an altered mental state.