Plasma cell disorders are a group of diseases that affect the plasma cells, which are a type of white blood cell responsible for producing antibodies. These disorders include conditions like multiple myeloma, Waldenström macroglobulinemia, and monoclonal gammopathy of undetermined significance (MGUS). They can lead to an overproduction of abnormal antibodies, causing various health issues. Symptoms of plasma cell disorders may include bone pain, fatigue, and increased risk of infections. Diagnosis typically involves blood tests, imaging studies, and sometimes a bone marrow biopsy. Treatment options vary depending on the specific disorder and may include chemotherapy, targeted therapy, or stem cell transplantation.