Ivory vertebral body from prostate cancer metastasis

Findings

Figure 1: Lateral Rx of the neck shows dense C5 vertebral body (ivory vertebral body)

Differential diagnosis for ivory vertebral body:
- Metastases
- Lymphoma
- Paget disease
- Less common: Infection (low grade i.e. TB) or Idiopathic segmental sclerosis


Ivory vertebral body from prostate cancer metastasis



Ivory vertebral body refers to an increase in density of a vertebral body that retains its size and contours, with no change in the density and size of adjacent intervertebral disks. The added density may be diffuse and homogeneous and involve most or all of the vertebral body, giving it a white appearance as opposed to the normal or possibly osteoporotic appearance of the rest of the vertebral column

Ivory vertebral body may be caused by numerous etiologies as listed above. Osteoblastic metastases elicit a sclerotic response in which vertebral body spongiosa is replaced with a dense, amorphous bony mass. In similar fashion, lymphomatous spread may cause an osteoblastic response leading to the dense changes. On the other hand, Paget disease usually causes an expansion of the contour of the vertebral body, which sometimes takes it outside of the definition of ivory vertebral body. You may also see reactive bone formation that occurs in response to stress leading to the appearance of an ivory vertebral body. This process is called idiopathic segmental sclerosis.

In children, the finding of ivory vertebra is rare. However, when found it is usually secondary to lymphoma, most frequently Hodgkin disease. Other less frequent causes include osteosarcoma, metastatic neuroblastoma, medulloblastoma or osteoblastoma. There have been rare cases of Ewing sarcoma causing dense vertebral bodies.

In adults, by far the most common cause is osteoblastic metastases from breast or prostate cancer. Other causes include osteosarcoma, carcinoid, Paget disease, and lymphoma. A radiopaque vertebral body is most compatible with a diagnosis of metastatic disease, and in the case of an elderly male would most likely be a result of prostate carcinoma. In a female patient, the most likely diagnosis would be breast carcinoma. Metastatic disease from breast carcinoma will not infrequently present as a solitary vertebral lesion.

Paget disease can present with a uniform appearance, however more often presents with a classic “picture frame” vertebral body where the contour of the vertebra is sclerotic with a relatively lucent center. The trabecular bone is also usually thickened leading to an expansion in the anterior-posterior and lateral dimensions.

Lymphoma can sometimes lead to sclerotic lesions in the vertebra including ivory vertebral body. It usually begins in a patchy fashion and leads to a more generalized pattern and sometimes even to an ivory vertebra pattern. Often you may also see the accompanying, invading soft tissue mass.

Osteomyelitis may also lead to sclerotic changes, however it is rarely found within only a single vertebral body. There are usually erosive changes found at the disk margins.

In general, the three causes that should be considered in the differential for ivory vertebral body are: metastatic cancer, Paget disease and lymphoma.