Incidence of Multiple Myeloma
Myeloma accounts for approximately 1 percent of all malignancies and 10 percent of hematologic tumors, representing the second most frequently occurring hematologic malignancy in the United States. At any one time, 50,000 people suffer from multiple myeloma symptoms, and approximately 15,000 cases are diagnosed each year. The median age at onset is approximately 65 years, although occasionally myeloma occurs as early as the second decade of life.
Multiple Myeloma Symptoms
Myeloma is a disease of neoplastic plasma cells that synthesize abnormal amounts of immunoglobulin or immunoglobulin fragments. Multiple Myeloma Symptoms are heterogeneous and include the formation of tumors, monoclonal immunoglobulin production, decreased immunoglobulin secretion by normal plasma cells leading to hypogammaglobulinemia, impaired hematopoiesis resulting in anemia and other cytopenias, osteolytic bone disease, hypercalcemia, and renal dysfunction.
Multiple Myeloma Symptoms are caused by tumor mass effects, cytokines released by the myeloma cells or indirectly by marrow stroma and bone cells in response to adhesion of tumor cells, and by the myeloma protein leading to deposition diseases (AL amyloidosis and light-chain deposition disease).
Etiology of Multiple Myeloma
The etiology of human myeloma is unknown. There have been several reports of families with an increased incidence of myeloma.
Classification of Multiple Myeloma
Myeloma belongs to a spectrum of disorders referred to as plasma cell dyscrasias. These include clinically benign conditions, such as essential monoclonal gammopathy and smoldering myeloma; rare and biologically intriguing disorders, such as Castleman disease and -heavy-chain disease; macroglobulinemia; solitary plasmacytoma with a high potential for cure when arising in soft tissue; and myeloma, a disseminated B-cell malignancy not curable with conventional-dose chemotherapy. All disorders share plasma cell morphologic features, and most are associated with the production of immunoglobulin molecules.
Although most plasma cell dyscrasias result from the expansion of a single clone of cells, with resultant monoclonal protein secretion, oligoclonal and polyclonal protein abnormalities accompany some conditions, such as Castleman disease or angioimmunoblastic lymphoproliferative disease, now recognized as a T-cell lymphoma.