MM-066: Primary Plasma Cell Leukemia: A Rare Entity with Four Cases

Abstract

Context Primary plasma cell leukemia (PPCL) is a rare hematological malignancy with an incomprehensible pathogenesis and a very aggressive course. Objectives Determining the risk factors that can cause the development of PPCL and affect its course was aimed. Design Four PPCL patients diagnosed at Gulhane Training and Research Hospital between March 2019 and June 2020 were evaluated in terms of laboratory and clinical course retrospectively. Patients or Other Participants The mean age of the patients at the time of diagnosis was 66 years (44–76), and males/females:1/1. None of the patients had a history of multiple myeloma (MM). Results Two patients presented with leukocytosis. Mean WBC was 59.625x103/mL (3800–197,000), average plasma cell in smear was 54.5% (20–100), mean plasma cell was 55,500x103/mL (600–188,000). Leukapheresis was applied to one patient. Anemia was detected in all, mean Hb was 9.9 g/dL. Thrombocytopenia was detected in 3 patients and mean platelet was 101x103m/L. Immunofixation results were IgG lambda in two, free lambda in one, and free kappa in 1 patient. Genetic results could not be reached. One patient was lost to follow-up and 3 patients were given bortezomib-cyclophosphamide-dexamethasone (VCD) in first-line treatment. Two patients died during follow-up, and mean survival was 77 days. One patient who was given 1 cycle VCD and 1 cycle lenalidomide-dexamethasone was lost to follow-up. ASCT could not be planned due to the short life span of the patients. Conclusion Incidence of PPCL is 0.4–1.2/million, progression from MM is seen in 0.5% cases. There is no difference between MM and PPHL in terms of CD38 and CD138 positivity, but CD56 is more frequently positive in MM and CD20 in PCL. CD27 positivity in PCL indicates increased anti-apoptotic activity. Discussion Approximately 150 multiple myeloma patients were followed up in our clinic between the same dates. Secondary PCL cases were not detected, and the fact that all of the diagnosed cases were PPCL created a picture incompatible with the incidence rates reported in the literature. Lambda monoclonality was shown in three of our patients, so it constitutes a feature for PPCL, unlike myeloma. Absence of genetic results is an important lack of our patients. More patients are needed for determination of risk factors in PPCL. It is necessary to identify poor prognostic indicators and urgently undergo transplantation in eligible patients using bortezomib-based treatment regimens.