Clinical Presentation

A 39-year-old woman presents with 1 week of increasing abdominal pain, fever, nausea, and vomiting.

(A) Contrast-enhanced computed tomography (CT) shows thrombus (arrowhead) at the confluence of the splenic and portal veins. The duodenal wall is markedly thickened (arrow) with a diffusely hyperdense pattern (also called the white attenuation pattern). (B) More caudal image shows thrombus (arrowhead) filling the superior mesenteric vein (SMV). Small-bowel (SB) wall thickening (arrow) is seen. (C) More caudal image shows more distal thrombus (arrowhead) in the SMV and distended jejunal loops (arrows) with marked mural thickening demonstrating the uniform white attenuation pattern. (D) Thrombus extends into peripheral branches (arrowhead), and thickened SB appears coalesced and masslike (arrows).

Differential Diagnosis

• SMV thrombosis: This is evidenced by the filling defect coursing throughout the SMV and its branches and the slow onset of symptoms. SMV thrombosis can be primary or secondary.