Multiple Myeloma (MM) is a disease which results from malignant proliferation of plasma cells. It is commonly encountered in elderly patients. Diffuse bony lesions are the most frequent thoracic involvement with MM. We report a case of 42-year-old male patient who came with pain and full swelling in the right chest wall since two years. On CT scan of thorax, heterogenously enhancing soft tissue density lesion with lytic sclerotic destruction of right 4(th) rib seen. En-bloc resection of third and fourth rib was done and plasmacytoma was confirmed on biopsy.