Fig. 2.

Various invasive patterns of adenocarcinoma with or without BRAF V600E mutation. (A) Acinar pattern. The entire sections of this tumor showed micropapillary and papillary predominant patterns with focal (less than 30%) acinar patterns. VE1 immunohistochemistry (IHC) was weak positive and BRAF V600E was confirmed by real-time polymerase chain reaction. (B) Most areas of this adenocarcinoma showed a papillary pattern. A micropapillary pattern was also presented but not predominant. VE1 antibody staining was strong positive. (C) A micropapillary dominant adenocarcinoma. The tumor also had a focal acinar pattern within central fibrosis (not shown), but the area’s volume did not exceed 30% of the total volume. VE1 IHC was diffuse and intermediate to strong positive. (D) The adenocarcinoma was mainly composed of a solid pattern. The tumor had high-grade nuclear atypia with abundant pale eosinophilic cytoplasm, and the stroma showed dense lymphocytic infiltration. VE1 IHC was diffuse and strong positive. (E) BRAF V600E–negative adenocarcinoma with papillary and micropapillary patterns. VE1 immunostaining was negative. (F) Solid pattern with VE1-negative staining (A–F, H&E staining and VE1 immunostaining, scale bar=200 μm).