Lobular carcinoma of the breast metastatic to the epidural space: a potential mimic of giant cell bone tumor

We report the case of a 64-year-old woman with a spinal epidural mass. Tissue from a decompression laminectomy disclosed a tumor with numerous osteoclast-like giant cells separated by small, moderately atypical tumor cells. The osteoclast-like giant cells were immunoreactive for vimentin, but negative for epithelial membrane antigen and broad-pectrum cytokeratin. Subsequent breast biopsy revealed a lobular carcinoma of classic type without osteoclast-like giant cells. This is the first reported case in which metastatic breast carcinoma was accompanied by these giant cells but the giant cells were not present at the primary tumor site.