Small bowel adenocarcinoma in Crohn disease: CT-enterography features with pathological correlation

Abstract

Identification of a mass being clearly visible suggests strongly the presence of small bowel adenocarcinoma in Crohn disease patients but adenocarcinoma may be completely indistinguishable from benign fibrotic or acute inflammatory stricture. Knowledge of these findings is critical to help suggest the diagnosis of this rare but severe complication of Crohn disease.

Crohn’s disease: prevalence of intestinal and extraintestinal manifestations detected by computed tomography enterography with water enema

“…Signs of neoplastic degeneration may be difficult to detect on CT images when inflammatory alterations are associated [5,29,30]. Both clinically and radiologically, the differentiation between disease-associated obstruction and obstruction resulting from adenocarcinoma is (arrow).…”

“…All the layers of the bowel are involved in CD, with the submucosal layer affected to the greatest extent [5]. The earliest pathological changes involve the submucosal lymphoid follicles and Peyer's patches which undergo hyperplasia followed by chronic suppuration and ulceration.…”

“…CD patients have a relative risk 15-50 times greater than that of the general population for developing adenocarcinoma in the small bowel, which is usually located in the jejunum and the terminal ileum, mirroring the distribution of inflammation. In almost all the cases of CD-related small bowel adenocarcinoma, there are adjacent foci of high grade epithelial dysplasia, thus suggesting a dysplasia-carcinoma sequence promoted by chronic mural inflammation, while sporadic small bowel adenocarcinoma is thought to develop following the adenoma-carcinoma sequence [5].…”

Computed tomography of Crohn’s disease: The role of three dimensional technique

“…Corresponding to the most common sites of inflammation in Crohn's disease pa tients, the most common sites of small bowel adenocar cinoma are in the distal and terminal ileum, as opposed to the general population, where small bowel adenocarci nomas are most common in the duodenum. The overall risk of small bowel adenocarcinoma may be 1550 times greater than in the general population, and are most com monly seen at the sites of greatest inflammation in each specific patient [25] . As a result, given the absence of any other clear means by which to screen the small bowel for tumors, the pos sibility of a tumor must be considered when evaluating any CT enterography study.…”

“…In a series by Soyer et al [25] , four different patterns were seen with Crohn's related small bowel adenocarcino mas: (1) focal soft tissue mass; (2) short severe stenosis; (3) long stenosis with wall irregularity; and (4) irregular circumferential wall thickening of a bowel loop. The use of VR techniques in the coronal plane can be particularly useful in some of these cases, nicely illustrating the irreg Axial contrast-enhanced image demonstrates multiple dilated loops of small bowel, in keeping with a small bowel obstruction.…”