A 71-year-old man was referred to the lung department with pain in the right side of the chest through three months, especially when physically active. The patient presented with a tendency to shortness of breath, fatigue, low energy level and night sweats. The tentative diagnosis of pleural tumour/metastases was made. Chest x-ray showed pleural thickening and poorly defined ribs on the right side, consistent with bone destruction. Computed tomography showed a big mass in the 5th rib and universal bone lesions. Biopsy from the rib revealed the diagnosis of myelomatosis.