Crohn's Colitis-Like Changes in Sigmoid Diverticulitis Specimens Is Usually an Idiosyncratic Inflammatory Response to the Diverticulosis Rather Than Crohn's Colitis

Abstract

The clinical outcome and optimum classification of patients who have sigmoid resection specimens that show the histologic features of Crohn's disease (CD) and diverticulitis is not well defined. Historically, these patients were considered to have coexistent diseases, but recent studies have suggested that the CD-like changes are part of the inflammatory reaction of the diverticulitis. Sorting out these issues has been complicated by the lack of distinction between patients with and without CD in other regions of the bowel, short clinical follow-up periods, and small numbers of patients. We report on the clinical outcome and histology of 29 patients who had sigmoid resection specimens with diverticulitis and CD-like changes. Of the 25 patients who had no prior or concurrent CD at the time of surgery, 23 remained free of CD during the follow-up period (median, 6.0 yrs) and two developed CD in other regions of the bowel. All four patients with CD prior to their sigmoid resection continued to have active CD postoperatively. There were no histologic features of the sigmoid resection specimens that could be associated with the outcome of the patient. These results suggest that CD-like changes within the sigmoid resection specimen are an idiosyncratic inflammatory response to the diverticulosis rather than coexistent CD in the overwhelming majority of patients who do not have prior or concurrent CD at the time of sigmoid resection. Pathologists should be wary about making the diagnosis of sigmoid CD in the context of diverticulitis unless there is CD in other parts of the bowel.

Segmental colitis associated with diverticulosis syndrome

“…In Crohn's disease, as well, studies have shown that over 80% of adults are usually diagnosed well before age 40 [6][7][8] . Like other forms of idiopathic inflammatory bowel diseases, the cause and pathogenesis needs to be better characterized and elucidated [1,5,9] . Endoscopic examination reveals a localized sigmoid inflammatory process with normal rectal and proximal colonic mucosa.…”

“…In recent years, other less common, but distinct types of inflammatory disease have become better recognized. One segmental form associated with diverticulosis, usually involving only the sigmoid colon, is the so-called "SCAD syndrome", or more precisely, segmental colitis associated with diverticulosis (SCAD) [1][2][3][4][5] .…”

A contemporary and critical appraisal of ‘indeterminate colitis‘

“…In one study of 29 patients with CDlike diverticulitis, only two developed CD, and both of these occurred in other regions of the bowel. 89 As mentioned above, many types of drugs may cause chronic or chronic active colitis that mimics IBD, in both biopsy and resection specimens. Ipilimumab, a drug used for the treatment of metastatic melanoma, has been reported to show UC-like inflammatory changes in the colon.…”

“…[86][87][88] Rarely, acute diverticulitis may mimic CD in resection specimens. 89,90 This phenomenon may be recognized by the fact that CD-like changes are isolated to the segment of colon involved with diverticular disease. In one study of 29 patients with CDlike diverticulitis, only two developed CD, and both of these occurred in other regions of the bowel.…”

The Differential Diagnosis of Colitis in Endoscopic Biopsy Specimens: A Review Article

“…Studies suggest that Crohn-like changes within the sigmoid that harbors diverticular disease are an idiosyncratic inflammatory response to the diverticulosis rather than coexistent CD in the overwhelming majority of patients who do not have a prior diagnosis of inflammatory bowel disease. 59 Pathologists should be cautious about making the diagnosis of sigmoid Crohn colitis in the context of diverticulitis unless there is CD in other parts of the bowel.…”