Diagnosis requires a plasma cell count of >2000 if the total leukocyte count is >10,000/microL or 20% plasma cells if the circulating white count is <10,000/microL.
Patients who have criteria for multiple myeloma and who have 5% to a more circulating plasma cells should be considered as having plasma cell leukemia.
If there is no previous history of multiple myeloma the process is considered primary, and if there is preceding history of multiple myeloma it is considered a eecondary plasma cell leukemia.
Secondary plasma cell leukemia occurs late in the course of multiple myeolma and has a worse prognosis than primary plasma cell leukemia.
In a study of 291 patients in the SEER database over years 1973-2004 the median age was 67 years, with an overall survival of 4 months, and survival was unchanged compared to improvements for multiple myeloma (Ramsingh G).
Patients more likely to have extramedullary disease, increased disease burden, more renal impairment and more cytopenias compared to patients compared to patients with myeloma (Garcia-Sanz R).
Patients with plasma cell leukemia have a survival that is significantly worse than patients with high risk myeloma.
It is associated with a four year survival of 28%, even among patients receiving hematopoetic stem cell transplantation.