Waldenström macroglobulinemia with cryoglobulinemia revealed by amorphous deposits on blood smear

Abstract

We report the case of an 86-year-old woman who presented with a 2-month history of anemia (9 g/dL) and weight loss. She had a medical history of arthrosis and hyperuricemia. Blood tests showed a normocytic aregenerative anemia with mean corpuscular hemoglobin concentration (MCHM) of 31.6 %, platelets 217 9 10/L, white blood count 3.3 9 10/L with lymphopenia (0.66 9 10/L) associated with elevated CRP (62 mg/L) and hypoproteinemia (58 g/L). TSH and creatinine were normal. Ultrasound and computed tomography revealed a hepatosplenomegaly, and positron emission tomography showed increased uptake in a right inguinal lymph node, biopsy of which revealed no tumor infiltrate. Examination of the blood smear showed amorphous lightly basophilic deposit mimicking white cells or platelet aggregates. The deposits had the same color and appearance as immunoglobulin inclusion in Mott cells, suggesting cryoglobulinemia. Laboratory tests confirmed the presence of cryoglobulin, characterized as an IgM lambda monoclonal protein (3.5 g/L). Due to the lack of evident etiology of this anemia, a bone marrow aspiration was done; smear examination revealed significant infiltration (83 % of the cells) by lymphoplasmocytoid cells which, with the cryoglobulinemia, permitted the diagnosis of Waldenstrom macroglobulinemia. Revelation of lymphoid hemopathy by cryoglobulin precipitates on blood smear remains rare and atypical [1]. The presence of cryoglobulin frequently results in erroneous WBC or platelet counts with pseudoleukocytosis or pseudothrombocytosis [2], whereas in our case