Figure 2: Histological and immunohistochemical findings in the autopsy specimens
A) Tumor cells can be seen in the lymphatic vessels below the pleura (arrows), resulting in a state of carcinomatous lymphangiosis(H.E. staining: original magnification x 100).
B) The metastatic lesions were composed almost entirely of highly malignant granular cells having high nuclear to cytoplasmic ratio and hyperchromatic enlarged nuclei (H.E. staining: original magnification x 200).
C) The tumor cells observed in some metastatic regions showed rather less-pleomorphic histological features, including lower nuclear-to-cytoplasmic ratios and inconspicuous nucleoli (H.E. staining: original magnification x 200).
D) The cytoplasmic granules stained positive for S-100 protein (Immunohistochemistry: original magnification x100).
E) Membranous expression of β-catenin with weak cytoplasmic staining was observed; however, no nuclear staining was seen (Immunohistochemistry: original magnification x 100).
F) The tumor cells showed no membranous staining for EGFR (Immunohistochemistry: original magnification x 100).