Pathoanatomical and radiographic findings in spinal breast cancer metastases.

Spine specimens infested with breast cancer metastases, ranging from localized seed of small tumor deposits to massive invasion and vertebral collapse, were frozen in situ, removed, examined with both conventional radiography and high resolution computed tomography (CT), and then studied in great detail by serial cryoplaning. The majority of metastases in the total of 53.5 vertebrae were lytic, and most were in close contact with the vertebral wall or the endplates. Depressions and defects of the endplates were associated with compensatory expansion of the intervertebral discs. Although lytic lesions abutting endplate defects had the radiological appearance of metastases, all contained herniated disc material rather than tumor. Only four of the 29 grossly destroyed and collapsed vertebrae showed extrusion of the posterior vertebral wall into the spinal canal. Tumor growth in the epidural space was rare. There were no macroscopical reactive changes of the osseoligamentous or neurovascular spinal elements to the metastases, but abnormalities of the posterior elements (kissing spines, facet joint subluxation, and pars interarticularis failure) were common.