Massive tumor invasion into the portal venous system in an operated case of adenocarcinoma of ascending colon.

Malignant portal vein thrombosis in colon carcinoma is very rare. We report a rare case of tumor invasion into the portal venous system in an operated case of adenocarcinoma of ascending colon in a 55-year-old lady. On contrast-enhanced CT, circumferential asymmetric wall thickening was seen in the cecum and ascending colon with enhancing filling defect in the middle colic vein, suggestive of tumor thrombus. The findings were confirmed intraoperatively and an extended right hemicolectomy was performed. Adjuvant chemotherapy was planned, but she was lost to follow-up and returned four months later with abdominal pain and loss of appetite. On contrast-enhanced CT, an expansile filling defect was seen within the main portal vein, the right and left portal vein, their segmental branches, the superior mesenteric vein, and the splenic vein, showing streaky contrast enhancement suggestive of malignant thrombus. No local recurrence or hepatic metastasis was seen. The patient was kept on supportive care.