Plasma cell leukemia (PCL) is a rare, yet aggressive form of multiple myeloma characterized by high levels of plasma cells circulating in the peripheral blood. PCL can either originate de novo (primary PCL) or as a secondary leukemic transformation of multiple myeloma (secondary PCL).
The epidemiology, clinical presentation, diagnosis, prognosis, and treatment of plasma cell leukemia are discussed here. The related disorders of multiple myeloma and plasmacytoma are presented separately. (See "Clinical features, laboratory manifestations, and diagnosis of multiple myeloma" and "Diagnosis and management of solitary extramedullary plasmacytoma" and "Diagnosis and management of solitary plasmacytoma of bone".)
Plasma cell leukemia (PCL) is a rare variant of multiple myeloma that presents either as a progression of previously diagnosed multiple myeloma (ie, secondary PCL) or as the initial manifestation of disease (ie, primary PCL). Historically, the majority of cases have been primary PCL (60 to 70 percent), although the incidence of secondary PCL may be increasing, perhaps due to the longer survival of myeloma patients, such that the distribution of disease is more evenly split [1,2]
The most extensive data on the epidemiology of PCL come from a series of 291 patients identified in the Surveillance, Epidemiology and End Results (SEER) database between 1973 and 2004 . During this period, approximately 49,000 patients with multiple myeloma were identified, for a relative incidence of 0.6 percent. In this series there were no significant differences based upon gender, age, or race when compared with patients with multiple myeloma. This SEER study did not distinguish between primary and secondary PCL.
PCL occurs in all races and all geographic locations. The incidence of PCL in Europe is approximately 4 cases per 10,000,000 persons per year . As with multiple myeloma, PCL is more common in African Americans and blacks from Africa than in whites .