Ivory vertebra

 The term “ivory vertebra” can be defined as a solitary homogeneously radiodense vertebral body with retention of normal size and contours and no changes in adjacent intervertebral disks1.The ivory vertebra sign can be seen in both adults and children.

The radiologic finding of a “white” vertebral body is observed in various conditions. Osteoblastic metastases stimulate osteoblasts results in the replacement of vertebral body spongiosa with dense and amorphous bony mass. Metastases occur most commonly from prostate, breast and lung in adults. Primary malignant diseases which can mimic solitary ivory vertebrae includes Ewing’s sarcoma, osteoblastic sarcoma, and Lymphoma.

Paget disease can simulate an ivory vertebra. Paget disease, however, usually causes expansion of the vertebral body contour, thereby limiting the ability of a vertebra affected by Paget disease to fully conform to the definition of an ivory vertebra.

Reactive bone formation (also called idiopathic segmental sclerosis) develops in a healing fracture, can give the appearance of an ivory vertebra.

Idiopathic ivory vertebra is characterized by fortuitous discovery in the lumbar or dorsolumbar area in adults 30–50 years of age with a slightly higher frequency in women. The vertebra is asymptomatic and the physical examination is usually nonrevealing with essentially normal routine blood tests4.
Inflammatory conditions like sarcoidosis5, tuberculosis can stimulate osteoblasts giving the typical ivory vertebrae appearance.

Mastocytosis is a rare disorder extending to a variety of focal and systemic diseases in which the common finding is mast cell hyperplasia or neoplasia. When it involves the bone, it can cause both osteoblastic or osteoporic reaction.