No intraperitoneal free gas is identified. Small amount of intraperitoneal free fluid, mostly in the right paracolic gutter.
Marked mural thickening of a 4.5 cm segment of distal sigmoid colon, with obliteration of the lumen, and marked dilatation of large bowel proximally (up to 10 cm). There is no transit of the rectally administered contrast, confirming obstruction. Absence of dilatation of small bowel is in keeping with ileocaecal valve competence.
Perirectal and perisigmoid fat stranding, with prominent lymph nodes (measuring up to 6 mm) is suspicious transmural spread of tumour, with thickening of the mesorectal fascia.
Prominent lymph nodes also demonstrated along the inferior mesenteric vascular bundle.
Mild mural thickening and a featureless appearance of the entirety of the sigmoid and descending colon are consistent with longstanding ulcerative colitis. Mucosal hyperenhancement and mesenteric hyperaemia suggest superimposed active inflammation Prominent concentric mural thickening of two short segments, at the junction of the descending and sigmoid colon and in the mid descending colon, are suspicious for synchronous lesions. Small focus of mural thickening in the posterolateral descending colonic wall may represent a polyp or a residual haustral fold.
No enlarged pre or paraaortic lymph nodes.3 mm hypodense lesion within segment 7 of the liver, stable in appearance since the previous study, is too small to further characterise.
Left renal simple cortical cyst.
Patchy airspace opacity in the posterobasal segment of the right lower lobe, likely representing aspiration in this context.
Conclusion:
Obstructing sigmoid annular constricting mass, in keeping with the patient's known carcinoma, with marked large bowel dilatation.