Dual light chain extramedullary myeloma presenting with mediastinal lymphadenopathy and lytic bone lesions

Light-Chain Myeloma Presented as Osseus Tumors: A Case Report

Light-chain multiple myeloma (LCMM) is a rare subtype of plasma cell neoplasm, usually linked to kidney involvement and lytic bone lesions. However, case presents as osseus tumors are very uncommon. A 63-year-old male patient complained of persistent rib pain. Computed tomographic imaging showed an isolated bone tumor in the eighth rib. Further positron emission tomography-computed tomographic scan revealed multiple lytic bone lesions in other areas. Biopsy of the rib lesion confirmed the presence of plasma cells producing kappa light chains. The patient received 4 cycles of daratumumab, bortezomib, lenalidomide, and dexamethasone treatments, resulting in significant improvement. Reviewing literatures, osseus tumor with osteosclerotic lesions has been rarely described in LCMM, underlining the challenge in diagnosis and stressing the importance of considering LCMM in the differential diagnosis of bone tumors.

An Overview of Light Chain Multiple Myeloma: Clinical Characteristics and Rarities, Management Strategies, and Disease Monitoring

Light chain multiple myeloma (LCMM) constitutes approximately 15% of patients with multiple myeloma (MM). It has a poorer prognosis when compared to immunoglobulin (Ig) G or IgA variant. We performed a comprehensive literature search on LCMM and identified a total of 390 articles. After a detailed screening, six studies involving a total of 1054 LCMM patients were included. A literature review revealed bone pain and renal failure as the most common initial sign and symptoms while extramedullary disease (EMD) was acquired later during the progression of the disease. Bortezomib has shown superior efficacy in LCMM patients over nonbortezomib regimens as demonstrated by better overall response rate (95.5% vs. 60%), progression-free survival (PFS) (25% vs. 9% at two years), and overall survival (OS) (24% vs. 9% at five years). Moreover, better PFS was seen, when bortezomib was used in combination with bendamustine compared to dexamethasone (95% vs. 25% at two years). Similarly, better OS (90% at two years) was observed with bortezomib in combination with bendamustine. Monitoring of disease should include serum free light chain levels, as literature review revealed that serum assays were more sensitive in indicating the disease and predicting PFS and OS as compared to urine assays. We provide presentation patterns, clinical rarities, management strategies including their efficacy, and disease monitoring in patients with LCMM in our review paper.