Nonsteroidal anti-inflammatory drugs can also induce different patterns of colitis, including microscopic colitis (lymphocytic or collagenous), focal active colitis, IBD-like colitis, or ischemic colitis (2) (discussed in subsequent sections).
Colonic biopsies show 2 patterns: a focal active colitis pattern, subsequently discussed in the section on drugs causing focal active/self-limiting colitis, and a pattern resembling GVHD.
If acute infections, Crohn disease, and ischemia have been ruled out, drugs--most commonly NSAIDs (30) and sodium phosphate (31) bowel preparations--should always be considered as a potential cause of focal active colitis. Focal active colitis is a histologic pattern of injury, not a specific diagnosis; it is defined by single or multiple, isolated foci of acute cryptitis, with normal intervening mucosa and small numbers of neutrophils within lamina propria or within surface epithelium.
The most common pattern of colonic toxicity associated with ipilimumab use is focal active colitis, with isolated crypt destruction, loss of goblet cells and regenerative epithelium, and neutrophilic infiltrates in the crypt epithelium.
It is important for the pathologist to keep in mind that a single drug type can induce many histologic patterns: NSAIDs, probably the most common medication used presently, can induce isolated mucosal erosions, ulcerations, focal active colitis, microscopic colitis (especially collagenous colitis), and, rarely diaphragm disease; MFA-induced injury may mimic GVHD, IBD, focal active colitis, and even ischemic colitis.
2009 Diagnosis Expert Diagnosis 1 Changes consistent Reflux esophagitis with reflux esophagitis 2 Intramucosal Intramucosal adenocarcinoma adenocarcinoma (stomach) 3 Adenocarcinoma, Gleason Adenocarcinoma, Gleason 3 + 3 3 + 3 (prostate) 4 Chronic active colitis Focal active colitis
(a) These were cases in which expert review determined that the original, microscope slide diagnosis was better than the review diagnosis from the digital image.
This later finding, which we term focal active colitis, can be confused with smoldering CD and/or ischemia.
The presence of focal active colitis in a patient who does not have a history of chronic inflammatory bowel disease should be interpreted conservatively, as the vast majority of cases turn out to be self-limited.
The clinical significance of focal active colitis. Hum Pathol.
Focal active colitis: a prospective study of clinicopathological correlations in 90 patients.