Characteristics

• Commonest primary malignant tumour in adults.

• > 95% occur over 40 years of age. Extremely rare before 30.

• Male predominance 2:1.

• Usually occurs in multiple sites (vertebra, ribs, skull, shoulder, pelvis and long bones). Solitary plasmacytomas seen in vertebral bodies, pelvis and femur.

Clinical features

• Majority present with bone pain. Beware adult with back pain which has changed in character or is associated with systemic upset (fatigue, weight loss).

• May present with anaemia, renal impairment, hypercalcaemia and proteinuria.

• Approximately 50% will have Bence–Jones proteins in the urine.

• Serum electrophoresis may show monoclonal bands.

Radiological features

• Early features include widespread osteoporosis with prominence of the trabecular pattern especially in the spine.

• Osteolytic lesions may be punched out (skull and long bones) or expansile (long bones, ribs and pelvis).

• Vertebral bodies are generally involved prior to the pedicle involvement in comparison to metastatic involvement.

• Involvement of the mandible; rare in metastatic disease.

• Subtle soft-tissue masses may be detectable adjacent to areas of bone destruction.

• Sclerotic lesions are rare and may be secondary to treatment.

• Bone scans can be normal and need correlation with plain radiographs.

• MRI – shows replacement of normal marrow (sensitive).

Management

• Myeloma management includes adequate hydration (to minimise renal problems), combination chemotherapy and bone-marrow transplant.

• Localised bone pain treated with radiotherapy.

• Prophylactic intramedullary nailing of impending long-bone fractures.