The patient went on to have a biopsy. 

Histology

The biopsy consists of myxoid tissue containing polygonal cells with prominent cell borders and pink cytoplasm. Some of the cells are vacuolated. Immunohistochemistry has been carried out and this shows that the tumor cells stain strongly with both epithelial markers (pan-keratin, cam5.2, EMA) and with S100, typical of chordoma.

FINAL DIAGNOSIS: chordoma