Acute leukemia/lymphoma of plasmacytoid T-cell type.

Plasmacytic morphologic characteristics are usually associated with cells of B-lymphocyte origin. Recently, plasmacytoid T-cells have been described in reactive lymph nodes and a rare form of lymphoma characteristically associated with myeloproliferative disorders. This report documents a case of plasmacytoid T-cell malignancy that initially presented as an acute leukemia in an elderly man with a longstanding myelodysplastic syndrome. The tumor replaced bone marrow and involved lymph nodes. Despite aggressive therapy, he died quickly of his leukemia/lymphoma. This case illustrates the need for complete cellular analysis in the diagnosis of morphologically plasmacytic malignancies and raises additional questions about the relationship of this peculiar type of T-cell to the hematopoietic marrow.