PAX8 and neoplasm: The tumor cells were markedly and diffusely positive for vimentin, alpha-inhibin (Fig. 3a), Melan-A (Fig. 3b), synaptophysin (Fig. 3c), NSE and CD56, and focally positive for pan-cytokeratin (AE1/AE3), but negative for PAX8, S100 and chromogranin A. The sustentacular pattern of S100 staining, typical in paraganglioma, was not observed in this case.