Multiple myeloma – Involvement of tibia and fibula

Figure 1. Protein electrophoresis showing M Band in the gamma globulin region

A 66 year woman presented with backache without evidence of spinal cord compression. The MRI showed a hyper intense signal in the body of the C2, D9, D12 and L3 vertebrae. The D11-12 disc was involved with an associated soft tissue component. A skeletal survey showed punched out lytic lesions in the skull, pelvis both femora, right tibia and fibula. A protein electrophoresis showed a 2.9g/dL monoclonal band in the gamma region. immunofixationelectrophoresis showed the band to be of IgGλ type. The λ free light chain was 443mg/L (normal 5.71-26.30 mg/L) and κ was 22mg/L (3.30-19.40 mg/L) with a free light chain ratio of 20. A bone marrow aspiration showed 50% plasma cells with 12% immature. Therapeutic options were discussed with the patient and as she did not want injectable she was initiated on treatment with a combinations with melphalan, prednisone, and lenalidomide.

Figure 2. X-ray skull showing punched out lesions

Figure 3. Lateral view of the skull showing punched out lesions

Bones commonly involved by multiple myeloma include spine 49%, skull 35%, pelvis 34%, ribs 33%, humori 22%, femora 13% and mandible 10%. Tibia (see below) is rare and fibula rarer.

Figure 4. Lytic lesion in the tibia and fibula