A 47 year-old man followed for chronic anemia presented to our service for a routine check. His medical history showed meningitis in childhood, depression, and chronic bronchitis. This patient occasionally drinks alcohol and has actively smoked, a pack a day, for 25 years. His hematological check-up revealed microcytic (Mean corpuscular volume: 67.4 fL) hypochromic (Mean corpuscular hemoglogin concentration: 28.7 g/dL) anemia (hemoglobin concentration: 10.7 g/dL) with a low ferritin (5 ng/mL) count and an increased IgM level (934 mg/dL), unchanged from prior visits. The lymphocyte count was normal (3900/μL), but the cytological analysis showed several lymphocytes of intermediate to large size with abundant moderately basophilic cytoplasm. The nucleus presented a quadrangular or bilobed form with a small nucleolus (Images 1 and 2). As cases of B-chronic lymphocytic leukemia with such cytology features had previously been described in the literature , flow cytometry immunophenotyping was performed and showed B-cell hyperplasia with polyclonality of light chains (Image 3). No additional investigation was conducted.
Polyclonal B lymphocytosis with binucleated lymphocytes first described by Gordon et al.  is a rare condition preferentially affecting young women who smoke heavily . Lymphocytosis is usually moderate. The etiology is unknown but tobacco plays an undeniable role. Family history and an association with HLA-DR7 have been described . An increase of polyclonal IgM is reported in all patients. The conventional karyotype or fluorescence in situ hybridization paradoxically may show a clonal abnormality with isochromosome 3 being found in most cases. Evolutionarily, lymphocytosis remains stable over time. This stability makes chemotherapy treatment unnecessary, but prolonged monitoring seems necessary because some authors have described the occurrence in rare cases of large cell lymphoma .