Metastatic Carcinoma Simulating Inflammatory Colitis

Spiral CT demonstration of hypervascularity in Crohn disease: “vascular jejunization of the ileum” or the “comb sign”

“…Metastatic breast carcinoma to the large intestine initially may be mistaken for an intrinsic inflammatory process such as granulomatous colitis [44] because the processes share several pathologic and radiolographic characteristics. These include unilateral mural involvement, nodular irregularities, pseudosaccular outpouchings, and the occasional appearance of ulcerations.…”

Linitis Plastica of the Rectum

“…2 Spread of tumor to the bowel may occur in a hematogenous manner (particularly breast carcinoma), 8 by direct invasion along the lymphatic vessels and mesenteric reflections, or by intraperitoneal seeding. 6,9 Each route accounts for approximately an equal number of cases of secondary neoplastic involvement of the bowel, and occasionally more than 1 mechanism of spread may be encountered. 9 The natural flow of ascitic fluid predicts where seeded peritoneal deposits will lodge 9 and is well illustrated in this case, in which metastatic deposits occurred in dependent areas of the abdomen: in the appendix (right paracolic gutter) and the anterior rectal wall (adjacent to the rectovesical pouch).…”

“…However, metastatic colonic linitis may simulate inflammatory colitis, particularly Crohn's disease, although tethering of mucosal folds is more likely to occur, and fistulas tend to be uncommon. 6 Computed tomography shows nonspecific concentric bowel wall thickening, but this finding may be subtle or attributed to inadequate distension. The main limitation of CT is that it does not have the resolution to show the individual layers of the rectal wall.…”

Carcinoma of the hepatic flexure with proximal lymphatic invasion mimicking Crohn's disease

“…Both these findings are characteristic of Crohn's disease. Later, irregular stenoses may occur, along with total loss of mucosal folds, pseudosacculations, and even ulcerations [4,5]. The changes usually affect predominantly the ruesenteric edge but changes may be diffuse if involvement is extensive.…”

“…Metastatic lesions to the colon caused by other mechanisms (hematogenous, intraperitoneal seeding, or direct invasion) may also give a radiographic appearance indistinguishable from Crohn's disease [4,5]. Only the presence of fistulous tracts allows correct diagnosis [4].…”