<prompt> Which of the following is the least common feature of Multiple Myeloma -Bone painNormocytic Normochromic AnemiaSusceptibility to bacterial InfectionHyperviscosity syndrome  <response>: Multiple myeloma is a malignant proliferation of plasma cells. Anemia will be of Normo or macrocytic type. Pancytopenia will be present which predispose to bacterial infection. Malignant plasma cells produce cytokines, which stimulate osteoclasts and result in net bone reabsorption. The resulting lytic lesions cause bone pain. Reference : Davidon, 23rd Edition, page no : 967. Hyperviscosity syndrome HVS is a combination of clinical signs and symptoms related to increased blood viscosity. It can result from abnormal plasma components such as paraproteins seen in Waldenstroms macroglobulinemia and multiple myelomaleast common or immune complexes systemic lupus erythematosis 