Figure 4.

Postoperative photomicrographs of lesion in adenocarcinoma portion. (a) The tumor cells formed irregular-shaped glands with infiltrating in the fibroblastic stroma and no gradual transition between adenocarcinoma and PSH was observed. (b) The tumor cells exhibited cytologically hyperchromatic nuclei, obvious nucleoli and mitotic figures (white arrow). There was no round cells found to distributed in the interstitial portion of gland structures. Immunohistochemically, tumor cells were positive for pancytokeratin (c), TTF-1 (d) and CEA (e). There was no TTF-1-positive round cell observed in this portion of mass (a, H&E staining with original magnification of 200 ×; b, H&E staining with original magnification of 400 ×; c-d, immunohistochemical staining with original magnification of 200 ×; e, immunohistochemical staining with original magnification of 400 ×).