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.