Primary plasma cell leukemia: a rare type of leukemia and plasma cell proliferation Plasma cell leukemia is defined by the presence of more than 20% plasma cells in the peripheral blood or a number of circulating plasma cells greater than 2G/L. The primary form: observed may be de novo, and may reveal a multiple myeloma until then unknown. This has similarities with multiple myeloma and has some special particularities that authors will expose in the light of a case diagnosed in the laboratory hematology Hassan II university Hospital of Fez.