(a) Obstructive portal venopathy due to metastatic breast carcinoma is seen at low power and is associated with periportal regenerative nodules (n), without fibrosis (nodular regenerative hyperplasia). The portal tract is shown at center, including its bile duct (bd) as well as portal vein branches (pv) filled with necrotic tumor. (b) The tumor thrombus within the portal vein branch shows extensive necrosis, with only a few clusters of preserved tumor cells at the periphery. (c) This portal tract (pt) shows breast carcinoma within the portal vein branch, growing with peripherally arranged tubular-glandular units and prominent central necrosis with calcification. (Hematoxylin and eosin stain, original magnification (a) ×40; (b) ×200; (c) ×40.)