A 69-year-old woman with a history of colon cancer presented to her local physician with progressive neck pain. Metastatic disease was suspected and radiographs showed a lytic lesion in the left pedicle of the C3 vertebra.
An open biopsy was performed.
Microscopically, there were large fragments of acellular fibrocartilage consistent with disc material. Embedded within these fragments were aggregates of cells with small, rather uniform nuclei and coarsely vacuolated cytoplasm.
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The above higher magnification image better documents the bland cell population with coarsely vacolated cytoplasm. Clearly, this is not the appearance of metastatic colonic adenocarcinoma.
As seen above, the vacuolated cells were strongly positive for cytokeratin.
As also seen above the vacuolated cells showed both nuclear and cytoplasmic positivity for S100 protein.
This is an example of a "chordoma wanna-be." There are multiple studies dealing with this family of small notochordal-related tumors under a variety of names including, "ecchordosis physaliphora," "notochordal remnants, "giant vertebral notochordal rests," and "benign notochordal cell tumor." Notochordal remmants, by definition, should be incidental findings with no associated radiographic abnormality. The other entities are typically associated with small sclerotic or, less commonly, lytic lesions without extraosseous extension. Benign notochordal cell tumors have been noted to be associated with chordomas and it has been suggested that chordomas may arise from these precursor lesions.
In the current case, the biopsy material clearly contains disc-like fibrocartilage, but the radiographs show apparent extension of the process into the adjacent osseous pedicle, though there is no extraosseous extension. This finding, coupled with the history of progressive pain led us to interpret this as simply a "notochordal cell tumor," eliminating "benign" from the diagnosis. Indeed, others have noted that in individual cases, it may not be possible to clearly distinguish "benign notochordal cell tumor" from a small chordoma. Accordingly, we believe that this patient should be followed for possible recurrent or progressive disease.