Inferior mesenteric arteriovenous fistula: Two case reports

Figure 1 Multi-detector computed tomography scan. A: Multifocal low densities in the enlarged left kidney with ureteral dilatation, periureteric and perirenal fat stranding, and a suspected pelvic stone (arrow), indicative of acute pyelonephritis; B: Sigmoid colon diverticulitis with wall thickening (black arrow), pericolic fat stranding, and mild fluid collection (white arrow); C: Edematous, thickened, and hypoenhanced wall of the sigmoid colon with adjacent fat stranding (arrows) observed in the arterial phase; D: Long-segment colonic wall thickening with reduced enhancement, submucosal edema, pericolic fat stranding; E: Mild fluid collection extending from the splenic flexure to the upper rectum (black arrows); F: No communication observed between the inferior mesenteric artery (black arrow) and vein (white arrow).

Figure 2 Colonofiberoscopy. A: Abnormal colonic mucosa exhibiting multiple ulcers, exudate, and hemorrhage from the splenic flexure to the upper rectum; B: Limited scope advancement to 23 cm from the anal verge revealed petechial hemorrhages, fragile and edematous mucosa, and vascular dilatation, consistent with ischemic colitis.

Figure 3 Multi-detector computed tomography angiography. A: Arteriovenous communication (black arrows) supplied by the dilated inferior mesenteric artery (black arrowheads); B: Venous drainage into the splenic (white arrow) and superior mesenteric veins (white curved arrow) via the marginal vein (white arrowheads); C: Prominent communication observed in the distal portion of the inferior mesenteric artery (black arrow); D: Early draining into the inferior mesenteric vein (white arrows) and marginal vein (white arrowheads).

Figure 4 Angiography of the inferior mesenteric artery. A: Nidus of the fistula (black arrows) supplied by the inferior mesenteric artery (black arrowheads); B: Prompt filling of the dilated marginal vein (white arrowheads) with drainage; C: The superior mesenteric vein (white curved arrow) and portal vein (white arrow). Invisible occluded inferior mesenteric vein; D: Nidus (black arrows) observed in the distal portion of the inferior mesenteric artery (white arrows); E: Early visualization of the inferior mesenteric vein (black arrowheads); F: Marginal vein (white arrowheads), with both showing a beaded appearance.

Figure 5 Exploratory laparoscopy. A: Extensively thickened mesentery and colon, hardened appendices epiploicae, and extensive saponified spots with yellow pus; B: Thickened mesentery and purplish colon with saponified appendices epiploicae; C: Arterialized inferior mesenteric vein (white arrow); D: High ligation of the inferior mesenteric artery (black arrows) and vein (white arrows); E: Side-to-end ileorectal anastomosis.