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. Since the first case was reported in 1967, knowledge regarding IgE-mediated MM is based on individual case reports. Based on the information available, it is thought that IgE-mediated MM presents clinically with the involvement of renal, bone, and hematological symptoms, which are the same as any other myeloma. However, the MM rarely involves the pleura, leading to malignant pleural effusion. We present a case of IgE-mediated MM with a unique feature of pleural effusion. The patient presented with constitutional symptoms of MM, which were followed by lab investigations revealing low hemoglobin, hypercalcemia, and high creatinine levels. An incidental computed tomography angiography (CTA) revealed lytic lesions in the spine. This was followed by skull and chest X-rays as part of the workup to determine the extent of the disease. It revealed further lytic lesions in the skull, humerus, and scapula, along with pleural effusion. This led to the suspicion of MM, which was ultimately confirmed by serum protein electrophoresis and a bone marrow biopsy. The patient was started on a triple regimen of bortezomib, thalidomide, and dexamethasone, which led to substantial improvement in his symptoms.