Primary Plasma Cell Leukemia.

Plasma cell leukemia (PCL) is a form of high-risk multiple myeloma comprising 1%-2% of new myeloma diagnoses, and defined by ≥ 5% circulating plasma cells. Classified as primary, de novo or secondary, from relapsed/refractory myeloma, PCL carries worse outcomes than conventional myeloma despite advances. Genomically, PCL demonstrates high-risk abnormalities like del(17p), 1q21 gain/amplification and overrepresentation of t(11;14), marking a distinct biological subgroup. Contemporary management involves quadruplet induction, early autologous stem cell transplantation in eligible patients, and multi-agent consolidation/maintenance. Immune effector therapies, especially BCMA-directed CAR-T, show promise for deeper, more durable responses. This review covers PCL biology, clinical features, prognosis, and treatment, emphasizing emerging therapies.