Multiple myeloma presenting as primary non-secretory plasma cell leukemia.

Primary plasma cell leukemia is a rare manifestation of multiple myeloma, whose neoplastic hierarchy in the classification of malignant hematological disorders is not yet very clearly defined. Morphological and immunological criteria indicate that the cells are at end stage of B cell maturation pathway. This unusual disorder is diagnosed by the presence of more than 2 x 10(9) plasma cells per liter of peripheral blood or more than 20% of the leucocytes being plasma cells on differential count. This occurs either denovo or as a terminal event in patients with long standing multiple myeloma. A case report of a young male patient with primary plasma cell leukemia is presented.