Update on infectious enterocolitides and the diseases that they mimic

Abstract

The anatomic pathologist's ability to diagnose infections, including gastrointestinal infections, in tissue sections has improved greatly in recent years. With the increasing number and availability of new molecular assays and immunostains, pathologists' understanding of the correlation between histologic patterns of inflammation and specific organisms or groups of organisms has expanded, as well as our understanding of how closely infections can mimic other frequently encountered diseases in gastrointestinal pathology (such as chronic idiopathic inflammatory bowel disease and ischemia). Anatomic pathologists continue to play a critical role in the diagnosis of gastrointestinal infections, as the examination of slides may provide a much more rapid result than microbiological cultures or other laboratory assays, and often cultures are not obtained before the patient is treated with antibiotics. Because many gastrointestinal infections are acquired through contaminated water and food, this review will focus primarily on food and water-borne infectious enterocolitides.

Pattern-based Histologic Approach in Very Early Onset IBD: Main Features and Differential Diagnosis

“…As shown in Table 2, a plethora of diseases can be associated with pathologic GI biopsies in young children. 10,15,17,18 As already underlined, diagnosis requires an integration of the main histologic pattern with clinical and laboratory findings. [18][19][20] Both CD-like and UC-like pattern should be initially distinguished from monogenic disease and PID.…”

Histopathology of Non-IBD Colitis. A practical approach from the Italian Group for the study of the gastrointestinal tract (GIPAD)

“…Many aspects of modern living also contribute to the transmission of enteric pathogens, such as water sports, camping, and consumption of raw or poorly cooked meat. Finally, the most recent immunosuppressive therapies in oncologic field increase the number of IFC cases 5 . Although many IFCs have a self-limited clinical course, post-infectious bowel syndrome with prolonged diarrhea or abdominal pain can occur in some patients, which requires a more in-depth clinical investigation.…”

“…Although many IFCs have a self-limited clinical course, post-infectious bowel syndrome with prolonged diarrhea or abdominal pain can occur in some patients, which requires a more in-depth clinical investigation. Endoscopic findings range from a quite normal to diffuse erythematous aspect of the intestinal mucosa; in some cases, an IBD-like appearance with aphthous ulcers can be discovered, raising the suspicion of Crohn’s or ulcerative colitis 5 . Histologically, many of these cases show a nonspecific inflammatory pattern associated with edema and congestion of the stroma but with no crypt distortion nor basal plasmacytosis 6 .…”

“…Histologically, many of these cases show a nonspecific inflammatory pattern associated with edema and congestion of the stroma but with no crypt distortion nor basal plasmacytosis 6 . In these cases, clinical integration with serological data and coproculture are needed for a correct diagnosis and identification of the pathogens 5 . On the other hand, infections due to spirochetes or protozoa can be easily detected on the mucosal surface, if present.…”

“…Mycobacterium can be identified by Ziehl-Neelsen stain or with bio-molecular PCR-based methods in caseating necrotic granuloma surrounded by multinucleated giant cells 11 . Yersinia enterocolitica infection causes intramural non-caseating granulomas often accompanied by stellate abscesses, usually located in the terminal ileum, mimicking the Crohn’s disease (IBD-like pattern) 5 . Finally, other pathogens, such as Enterohemorragic Escherichia coli and Clostridium perfringens, can lead to an ischemic-like pattern with haemorrhage associated to acute inflammation, marked oedema, crypt withering, and lamina propria hyalinization with mucosal necrosis 5 .…”