What is the most common primary malignancy of bone?

1. Multiple Myeloma

2. What does it look like on a bone scan?

   1. Bone scans are cold or normal except at sites of pathological fractures, which will be focally hot.

      1. This occurs because Multiple Myeloma causes the release of Osteoclast Activating Factor by the plasma cell. Bone scans depend on Osteoblastic activity. So when there is a fracture osteoblastic activity occurs.

3. Where is it primarily located

   1. Located primarily in the spine.

   2. Also located in the pelvis skull, ribs, and scapula.

4. Key clinical features.

   1. 75% of patients are between 50-70 yoa and 2:1 male preponderance

   2. LB Pain is the cardinal initial symptom relieved with bedrest and aggravated with weight. With sciatica

   3. Bacterial infections occur in 10% of cases most respiratory in nature.

   4. Pathological fracture is common complication

5. Key radiologic findings.

   1. Bone Scans are cold

   2. Gross osteoporosis may be the only early sign

   3. Punched lesions are the radiologic hallmark of myeloma

   4. Vertebra plana or wrinkled vertebra is characteristic.

   5. Raindrop skull (lytic myeloma defects) and pedicle sign of myeloma (preservation of pedicles) occur.

   6. “Moth Eaten,” Permeative lesions

   7. Foggy cortical – Medullary border

6. Key laboratory features.

   1. 40% show Bence Jones’ proteinuria.

   2. Immnoglobulin Electrophoresis – to Elevation of IgG

   3. May have infections do to decreased WBCs

   4. Normocytic, normochromic anemia

7. Prognosis

   1. 90% die within 3 years.

   2. Tx is usually radiotherapy, chemotherapy, and on occasion, local excision.

Category: Tumors Revision