Plasma cell
Plasma cell leukemia (PCL) is a plasma cell dyscrasia, i.e. a disease involving the malignant degeneration of a subtype of white blood cells called plasma cells. It is the terminal stage and most aggressive form of these dyscrasias, constituting 2% to 4% of all cases of plasma cell malignancies. PCL may present as primary plasma cell leukemia, i.e. in patients without prior history of a plasma cell dyscrasia or as secondary plasma cell dyscrasia, i.e. in patients previously diagnosed with a history of its predecessor dyscrasia, multiple myeloma. The two forms of PCL appear to be at least partially distinct from each other. In all cases, however, PCL is an extremely serious, life-threatening, and therapeutically challenging disease.