Waldenstrom Macroglobulinemia; Aged; Alemtuzumab; Aneuploidy; Antibodies, Monoclonal/therapeutic use; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal, Murine-Derived; Antibodies, Neoplasm/therapeutic use; Antimetabolites, Antineoplastic/therapeutic use; Antineoplastic Agents/therapeutic use; B-Lymphocytes/pathology; Blood Viscosity; Bone Marrow/pathology; Bone Marrow Transplantation; Chromosome Aberrations; Cryoglobulinemia/etiology; Female; Flow Cytometry; Humans; Immunoglobulin M/blood; Immunophenotyping; Incidence; Lymphoma/classification; Lymphoma/complications; Male; Middle Aged; Paraproteins/analysis; Plasmapheresis; Prognosis; Rituximab; Salvage Therapy; Waldenstrom Macroglobulinemia/blood; Waldenstrom Macroglobulinemia/diagnosis; Waldenstrom Macroglobulinemia/epidemiology; Waldenstrom Macroglobulinemia/pathology; Waldenstrom Macroglobulinemia/therapy