Figure 2. Photomicrographs of the tumor. Histopathological features of the four components of the collision tumor: ( 1 ) Oncocytic carcinoma with capsular invasion (H&E, 40x); ( 2 ) Conventional (classic) papillary carcinoma (H&E, 100x); ( 3 ) Hobnail variant of papillary thyroid carcinoma (H&E, 400x); ( 4 ) Poorly differentiated thyroid carcinoma (H&E, 400x).