Fig. 4.

a In the surgical specimen, spindle atypical cell and multinucleated giant cell infiltrate extensively. Necrosis, ghost-like papillary carcinoma and irregular nuclear fission are found. b Autopsy reveals that the tumor invades the adventitia of the common carotid artery (CCA) but not to the media in the region of neck surgery (red arrow). c The adventitia of the CCA is preserved at the non-dissected area in the left neck (black arrow). CCA common carotid artery, Tm tumor, ad adventitia, m media