338 Primary Plasma Cell Leukemia: Diagnostic Nuances in an Aggressive Dyscrasia

Introduction/Objective Primary plasma cell leukemia (pPCL) is an uncommon and aggressive plasma cell neoplasm, comprising less than 2% of cases. It often presents with circulating plasma cells and rapid progression, frequently lacking classic myeloma features like lytic lesions. Early diagnosis is critical but challenging due to its atypical and subtle clinical onset. Methods/Case Report We report a case of a patient who presented with a 2-week history of progressive fatigue, generalized weakness, and weight loss. Laboratory workup revealed severe anemia, thrombocytopenia, renal impairment (elevated creatinine), high LDH, and markedly elevated beta-2 microglobulin. Peripheral smear showed >20% plasma cells with rouleaux formation. Serum protein electrophoresis showed a sharp, well-demarcated band in the beta region. Flow cytometry of peripheral blood revealed 75% plasma cells. Bone marrow biopsy demonstrated diffuse infiltration with >70% plasma cells exhibiting immature morphology. Free light chain assay was elevated, but no Bence Jones proteins were detected in urine. Immunohistochemistry confirmed plasma cell lineage with CD138 and kappa light chain positivity. Imaging showed no lytic lesions; however, some extramedullary infiltration was noted in the liver. Results NA Conclusion Given its aggressive course and poor prognosis, prompt recognition and intervention are essential. Our report adds to limited literature and emphasizes diagnostic vigilance in atypical hematologic presentations.