ABSTRACT
Acute leukemias of ambiguous lineage represent a heterogeneous group of rare leukemias with adverse outcome. It includes mixed phenotype acute leukemia, much less common acute undifferentiated leukemia, and natural killer lymphoblastic leukemia. Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a highly aggressive neoplasm derived from the precursors of plasmacytoid dendritic cells, which involves the skin and often disseminates into other organs with leukemic blood and bone marrow involvement. Integrated genomic analysis using expression profiling and array-based comparative genomic hybridization demonstrated that BPDCN shows distinct gene expression profiles and distinct patterns of chromosomal aberrations compared to acute myelomonocytic leukemia involving the skin. Histiocytic sarcoma is a malignant tumor of the macrophage lineage. It occurs in the lymph nodes and extranodal locations including the skin, abdominal organs, soft tissue, and spleen. The concurrence of Hodgkin lymphoma and B-cell or composite lymphoma composed of T- and B-cell lymphomas occurs less often.
