Immunoglobulin E (IgE)-Mediated Multiple Myeloma Presenting as Pleural Effusion.

Multiple myeloma (MM) is a disease characterized by the abnormal production of plasma cells. These plasma cells have the property to produce immunoglobulins (Ig), on the basis of which MM can be classified. Immunoglobulin G is responsible for most of the cases, while IgE mediates the rarest form of MM.