Necrotizing colitis (NC) with perforation is a rare complication of the obstructive cancer of the right colon.

We report here a case of a 45-year-old female patient of mucinous adenocarcinoma of ascending colon, which presented as acute NC with perforation proximal to obstructing colonic carcinoma with their imaging features on computed tomography (CT). The purpose of this article is to highlight the role of CT in distinguishing an ischemic and a tumoral segment in the carcinomas complicated by proximal bowel ischemia.

Imaging plays a great role in distinguishing an ischemic and a tumoral segment in carcinomas complicated by proximal bowel ischemia. The identification of NC will help to accurately stage colonic cancer.

Satyam S, Jain K, Pradhan G. Necrotizing Colitis with Perforation Proximal to Obstructive Ascending Colon Cancer: A Case Report. Euroasian J Hepato-Gastroenterol 2022;12(2):95-97.

This study was performed to determine the frequency and patterns of obstructive colitis (OC) seen on F-FDG PET/CT scan of patients with adenocarcinoma of the colon and rectum.

Preoperative PET/CT scans and surgical records of 308 patients with surgically proven colorectal adenocarcinoma were retrospectively reviewed for the presence of colon obstruction and OC proximal to the colorectal adenocarcinoma. The distributions, patterns, and SUVmax of OC were evaluated on PET/CT. Abdominal CT, colonoscopic finding, and histopathologic findings of surgical specimen were also reviewed.

Of 308 patients, PET/CT scans of 29 (9.4%) showed OC. The mean SUVmax of OC was 3.6 ± 2.2 (range, 1.6-12.3). Obstructive colitis was contiguous to the tumor in 23 patients (79.3%) and noncontiguous in 6 (20.7%). Obstructive colitis was diffuse in 25 patients (86%) and patchy in 4 (14%). It was segmental in 16 patients (55%) and pancolonic in 13 (45%). Twenty-three of 29 patients (79.3%) showed proximal wall thickening to colon cancer on abdominal CT performed about 3 days before PET/CT.The patients with OC on PET/CT was significantly associated with annular (P = 0.017), large-sized (P < 0.001), and advanced colon cancer (P < 0.001). However, there was no association between tumor size and SUVmax of OC.Ten proximal polyps were detected in 7 of 29 patients (24.1%) on colonoscopy and surgical specimen. Of these, 1 proximal polyp was removed before PET/CT scan, whereas the remaining 9 were not detected on PET/CT scan.

Obstructive colitis is predominantly diffuse and contiguous with the obstructing adenocarcinoma. Colorectal cancer with OC tends to show annular shape and larger tumor size. Obstructive colitis may lower the possibility of detection of synchronous proximal colonic lesion by PET/CT.

The term "obstructive colitis" refers to ulceroinflammatory lesions occurring in the colon proximal to a completely or partially obstructing lesion. It has been referred to by various terms in the literature. This entity differs from the carcinoma of the colon that complicates true ulcerative colitis where there is involvement distal to the neoplasm as well as proximal to it. Although it has appeared in the literature over several decades, it remains an uncommon and troublesome disease. In Yonsei University Medical Center, for 11 years from January 1996 to December 2006 we encountered seven patients with obstructing colorectal carcinoma complicated by obstructive colitis. Here we report our cases to share our experience and to review the literature to facilitate the recognition and proper management of this rare disease entity.

This study was performed to determine the frequency and patterns of colon wall thickening seen on CT of patients with adenocarcinoma of the colon.

Preoperative abdominal and pelvic CT scans of 185 patients with surgically proven adenocarcinoma of the colon were retrospectively evaluated by three abdominal radiologists for the presence of colon obstruction and colon wall thickening proximal to the colon adenocarcinoma. The distributions and patterns of colon wall thickening were categorized by consensus. CT findings were compared with pathologic findings. Fisher's exact test was used to determine the statistical significance of any associations.

Of 185 patients, CT findings of 20 (10.8%) showed colon wall thickening. Of these, the adenocarcinoma obstructed the colon in 19 patients (p < 0.01). Colon obstruction was partial in 10 patients (53%) and complete in nine (47%). Colon wall thickening was contiguous to the tumor in 14 (70%) patients and noncontiguous in six (30%). Segmental and pancolonic, patchy and diffuse, and dependent and nondependent colon wall thickening was observed in 10 patients (50%) in each category. Associated small-bowel wall thickening was shown in 10 (50%) of the 20 patients. Pathologic examination showed colon wall thickening to be due to edema in all cases.

Colon wall edema can occur proximal to colon adenocarcinoma, is almost always associated with colon obstruction, and is predominantly contiguous with the obstructing adenocarcinoma.

To determine the importance of the finding of segmental wall thickening in the colonic loop distal to colonic carcinoma at computed tomography (CT) by means of histopathologic correlation.

Thirteen consecutive patients whose helical CT scans showed segmental wall thickening (>1 cm in maximal width, >5 cm in length) in the colonic loop distal to colonic carcinoma were included. The thickness and length of an involved segment, location, morphologic tumor type, CT patterns of wall thickening, and pericolic changes were evaluated. Surgical pathologic findings in all 13 patients were correlated with CT findings.

The involved segment distal to the colonic carcinoma showed circumferential wall thickening with a preserved wall layer pattern at CT. Pericolic changes of varying degrees were seen in 10 patients. Histopathologic examination revealed submucosal and subserosal edema (n = 6), chronic inflammation and fibrosis (n = 5), or both (n = 1), and no histopathologic alteration (n = 1). The tumors were mostly fungating (n = 11), larger than 5 cm in the greatest dimension (n = 12), located in the ascending colon (n = 10), and extended to pericolic adipose tissue (n = 11).

Colonic carcinoma, especially a large fungating type involving the ascending colon with pericolic infiltration, can produce segmental wall thickening in the distal segment at CT, which represents edema or colitis at histopathologic examination.

Obstructive colitis is an ulcero-inflammatory and necrotizing condition that occurs in the colon proximal to benign or malignant stenosing lesions. it is the result of ischemia due to impairment of blood supply secondary to elevation of the endoluminal pressure, distension of the colonic wall and other factors which impair adequate perfusion. The incidence among patients with colonic obstruction is reported at between 1 and 7%. Of 50 patients with this condition in this series, 30 female and 20 male, 2/3rds were well over 70 yrs of age. Obstruction was most common in the rectosigmoid. In half the patients this was due to adenocarcinoma, 24 were due to benign obstruction and 15 were caused by diverticular disease. Type, extent and depth of ischemic lesions were highly variable and comprised early mucosal hemorrhage and edema, ulcero-hemorrhagic lesions and transmural necrosis. There was always an abrupt transition between affected and normal bowel. A segment of preserved mucosa was usually present on the proximal side of the stenosis. In 16 patients massive dilatation with stretching and thinning of the bowel wall, associated with a blow-out type of perforation or with transmural necrosis, was observed and was considered to have resulted from a rapid rise of endoluminal pressure to high levels. The microscopic and macroscopic features are described in detail and histological factors discussed in relation to the pathological lesions encountered. Emphasis is placed upon the range of appearances and similarities are shared with other inflammatory colonic diseases, particularly idiopathic inflammatory bowel disease. The importance of recognition of this disease entity, not only by pathologists but by surgeons dealing with the disease at operation, is stressed.

Obstructive colitis is a condition that is not widely appreciated by pathologists. It is defined as an ulcero-inflammatory lesion(s) proximal to a colonic obstruction from which it is separated by a variable length of normal mucosa. Five cases are described which illustrate the clinico-pathological spectrum of the condition. All presented surgically as acute intestinal obstruction, secondary to adenocarcinoma in four cases and a diverticular stricture in one case. Pathologically, the severity of colitis ranged from a single discrete ulcer to an extensive area of fulminant colitis indistinguishable from colitis indeterminate. Furthermore, two cases represented 'obstructive enteritis', a variant of obstructive disease not previously reported. Microscopically, all cases were characterized by distinctive areas of localized ulceration and active inflammation, the features of which were quite unlike those of Crohn's disease or ischaemia, separated by islands of normal mucosa. The role of mural hypoperfusion and secondary localized ischaemia in the pathogenesis of this disorder is discussed. It is suggested that colitis indeterminate represents the final common pathological pathway of the intestine to a wide range of initial insults, be they obstructive or inflammatory.

Four cases out of 204 new cases of colorectal carcinoma seen in a 24 month period were proven to have concomitant proximal ischaemic colitis. Ischaemic colitis associated with obstructing carcinoma of the colorectum may present dramatically with gangrene or colonic perforation if the acute vascular insufficiency is severe. Less severe degrees of ischaemic insult must be recognised intra-operatively as the incorporation of ischaemic colon in a colonic anastomosis may result in an anastomotic leak. Two other patients with ischaemic colitis were wrongly diagnosed as colorectal carcinoma on colonoscopy. Endoscopic features of ischaemic colitis may mimic colonic carcinoma and endoscopic biopsy is essential where any doubt exist as to the possibility of ischaemic colitis so that unnecessary surgery may be avoided.

A case of obstructive colitis associated with rectal carcinoma in a 56 year old Japanese man is reported herein. He presented to Shinkokura Hospital with severe abdominal pain following a one month history of anal bleeding and mild abdominal pain. On palpation, muscle guarding was observed in the left lower quadrant and the white blood cell count was 14,200/mm3. An exploratory laparotomy was performed under the provisional diagnosis of acute abdomen, which revealed localized peritonitis 8 cm oral to an area of rectal carcinoma. An anterior resection of the lesion was therefore performed together with a descendo-proctostomy. The histopathologic diagnosis revealed adenocarcinoma and obstructive colitis involving the entire thickness of the sigmoid colon and resultant fibrino-purulent peritonitis. His post-operative course was uneventful and he was continuing to do well on the 30th postoperative day, at the time of writing. The clinical significance of this combination of obstructive colitis with rectal carcinoma is briefly discussed following the presentation of this case.

Experimental ischemic colitis proximal to artificial bowel obstruction was produced under poor regional circulatory conditions in rats. Only the vessels of the left hemi-colon were ligated to obtain poor circulation (ischemia). Two types of aluminum rings were used to obstruct the bowel at the most distal portion of the ischemic colon. One, with a 4 mm internal diameter, was used for the model of partial colon obstruction with ischemia (partial obstruction, n = 25) and the other, with a 2 mm internal diameter, was used for complete colon obstruction with ischemia (complete obstruction, n = 25). The circumference of the dilated bowel was larger in complete obstruction than in partial obstruction. Ischemic colitis developed in 9 of 25 rats (34.0%) with partial obstruction and 16 of 25 (64.0%) with complete obstruction. In terms of morphometry, over half of the ischemic lesions in complete obstruction were more than 1.0 cm2, but such a large size in partial obstruction was not observed. It was demonstrated that the depth of ischemic lesions gradually increased in extensive lesions. In conclusion, complete colon obstruction with ischemia frequently caused severer ischemic colitis, together with marked distention of the proximal bowel, than partial colon obstruction with ischemia.

Acute necrotizing colitis is a rare complication of colonic obstruction. Six cases occurring during a 20-month period are described. The presenting features were those of colonic obstruction with shock but without perforation. At laparotomy changes ranged from mucosal necrosis to frank gangrene in the colon proximal to the obstructing lesion. Gram stains of resected colon showed Gram-positive bacilli, resembling clostridia, invading the mucosa and submucosa. Two patients treated by defunctioning colostomy alone died but the remaining 4 survived after total colectomy. The cause is not known but raised intraluminal pressure may result in terminal mucosal ischaemia allowing anaerobic organisms to invade the bowel wall.

Patients with long-standing ulcerative colitis have an increased chance of developing a carcinoma of the colon, especially when the inflammatory process involves the entire colon, but no case of a carcinoid tumour of the colon occurring in a patient with ulcerative colitis has been reported.