LETTER TO THE EDITOR Reactive plasmacytoses can mimick plasma cell leukemia: Therapeutical implications C. TOUZEAU, C. PELLAT-DECEUNYNCK, T. GASTINNE, F. ACCARD, G. JEGO, H. AVET-LOISEAU, N. ROBILLARD, J. L. HAROUSSEAU, R. BATAILLE, & P. MOREAU Hematology Department, CHU Ho ˆtel-Dieu, Nantes, France (Received 27 July 2006; revised 6 September 2006; accepted 12 September 2006) Plasma cell leukemia (PCL) is defined by an absolute plasma cells (PC) number greater than 2 6 10 9 L 71 or a relative number greater than 20% of peripheral white blood cells [1]. PCL represents less than 5% of malignant plasma cell disorders and the outcome of patients with PCL is extremely poor with a median survival less than 1 year in most cases [2 – 4]. The IFM group reported in a series of 40 cases with PCL that 11 patients died within the first month of diagnosis, indicating that cytoreductive therapy is urgently required when the diagnosis is made [4]. Nevertheless, before initiating cytotoxic therapy, including alkylating agents and/or dexamethasone, one must eliminate the diagnosis of reactive plasma- cytosis (RP). We here report three cases of RP observed in our department over a 3-year period (Table I). In each case, the number of circulating PC (Figure 1) was superior to 2610 9 L 71 in the peripheral blood with anemia, hypergammaglobulinemia on electro- phoresis and the disease mimicked PCL. Careful evaluation revealed that hypergammaglobulinemia was polyclonal and flow cytometry showed that circulating PC was polyclonal and presented a shared Table I. Patients’ characteristics. Case 1 Case 2 Case 3 Age/sex 77/F 80/F 79/F Cause of hospitalization Fever Purpura Dyspnea, fever Leukocytes (10 9 L 71 ) 84.680 25.0 11.7 Circulating PC (10 9 L 71 ) 44.880 21.6 4.2 Hb (g dL 71 ) 7.1 10.5 8.2 Platelets (10 9 L 71 ) 97 147 91 Protein (g L 71 ) 96 115 93 IgG (g L 71 ) polyclonal (41.7) polyclonal (66) polyclonal (36) % PC (bone marrow aspiration) 80 ND 56 PC cytogenetics Normal ND Normal PC phenotype CD19þ, 38þ, 138þ, 40þ, 45þ, 567, 27þ, 287 CD19þ, 38þ, 138þ, 40þ, 45þ, 567, 27þ, 287 CD19þ, 38þ, 138þ, 40þ, 45þ, 567, 27þ, 287 Bone lesions No No No Calcium Normal Normal Normal Bence Jones proteinuria Negative Negative Negative Cause of RP Septicemia (E. coli) Sjogren’s syndrome Pneumonia (not documented) Outcome Death due to septicemia Favorable Favorable with IV antibiotics Correspondence: Philippe Moreau, MD, Hematology Department, CHU Ho ˆ tel-Dieu, Place Alexis Ricordeau, 44093 Nantes cedex 01, France. Tel: 33 2 40083271. Fax: 33 2 40083250. E-mail: philippe.moreau@chu-nantes.fr Leukemia & Lymphoma, January 2007; 48(1): 207 – 208 ISSN 1042-8194 print/ISSN 1029-2403 online Ó 2007 Informa UK Ltd. DOI: 10.1080/10428190601016159