BACKGROUND.
The prevalence of radiologically invisible metastatic tumors to bone is not known. To clarify this, the authors examined histologic sections, radiographs, bone scans, and magnetic resonance (MR) images of autopsied patients with bone metastases.
METHODS.
Complete slices of the vertebral column, including C3-S1, were obtained from 52 cadavers with metastatic tumors to the spine. Macroscopic and histologic features were compared with postmortem roentgenographs (52 patients), bone scans with gY"'Tc-labelled methylene diphosphonate (17 patients), and MR images (4 patients). Morphologic patterns were classified into intertrabecular, osteoblastic, osteolytic, mixed, small lesion, and compression fracture.
RESULTS.
Metastatic lesions were found in 734 of the 1194 vertebral bodies. The lesions were intertrabecular in 255 vertebrae, osteoblastic in 185, osteolytic in 114, mixed in 70, small lesion in 83, and compression fracture in 27. Postmortem radiographs demonstrated lesions in 367 (50%) of the 734 vertebrae, bone scans in 103 (34.7%) of the 297 vertebrae examined, and MR images in all 42 (100%) vertebral bodies imaged. Lesions showing an intertrabecular pattern were detected in only 7.1% of the radiographs and 4.5% of the bone scans.
CONCLUSIONS.
Radiographs and bone scans often fail to show metastatic lesions, especially those with an intertrabecular pattern. The intertrabecular pattern is a unique histologic form that is difficult to detect on radiographs and bone scans.