Which condition is characterized by a high concentration of monoclonal IgG and bone lesions?

Multiple myeloma is characterized by the proliferation of monoclonal plasma cells in the bone marrow, leading to the overproduction of monoclonal immunoglobulin (often IgG). This increased concentration of monoclonal IgG can be detected in the serum or urine, often referred to as M-protein.

The disease is also associated with characteristic bone lesions, which can present as lytic lesions on imaging studies due to the osteoclast-activating effects of the neoplastic plasma cells. These lesions contribute to the bone pain frequently reported by patients and can lead to other complications such as fractures and hypercalcemia.

Other conditions, while they may involve the bone or abnormal proteins, do not have the specific combination of high monoclonal IgG levels and the distinct bone lesions seen in multiple myeloma. For instance, hepatic encephalopathy is a metabolic condition related to liver dysfunction, neuroblastoma is a solid tumor often found in children, and renal cell carcinoma (RCC) primarily involves the kidneys and may metastasize to bone but is not typically associated with a monoclonal IgG spike. Thus, the hallmark of multiple myeloma distinctly aligns with both the high levels of monoclonal IgG and the