Editorial on ECCO Topical Review on Clinicopathological Spectrum & Differential Diagnosis of IBD
Ann Driessen, H-ECCO Member
Inflammatory Bowel Disease is a longstanding recurrent inflammatory disorder that is most prevalent in Western countries but is increasing in Asiatic countries. The worldwide increase in the incidence of IBD, comprising Crohn’s Disease, Ulcerative Colitis and IBD unclassified, is having a significant impact on health care systems. Achievement of an optimal quality of care of IBD requires a multidisciplinary approach by different clinical disciplines, including pathology. Histopathology plays an essential role in the diagnosis and management of IBD. The pathologist excludes or confirms and subtypes IBD, assesses its activity and response to treatment and diagnoses preneoplastic lesions on endoscopic biopsies. Suboptimal sampling during endoscopy or insufficient clinical information, however, hampers the pathologist in making a diagnosis . The main histological features of IBD are disturbance of the architecture and basal plasmacytosis, though a wide variety of disorders resemble IBD not only clinically and endoscopically but also histologically. Distinction between IBD and these mimics is essential as misdiagnosis results in delayed and incorrect management. Their differentiation is, however, not always straightforward and, in addition to a standard clinical examination, requires serology, imaging, endoscopy, histology and other investigations .
ECCO set up a consensus group of experts in gastroenterology and pathology to position statements, which were recently published in the article “ECCO Topical Review on Clinicopathological Spectrum & Differential Diagnosis of IBD” . The aim was to explore the clinical presentation of IBD and its mimics, pathological mimicry of IBD and the value of ancillary techniques. The focus of the Topical Review is on the diagnosis, differential diagnosis and management of IBD and these mimics. A systematic literature review was performed by 15 experts, organised into three working groups. Based on literature data, a draft text, including Current Practice Point Statements, was written. Since there is limited evidence-based information, a core feature of a Topical Review is the expert opinion consensus meeting. During this meeting the Current Practice Point Statements were discussed and those achieving 80% or more agreement among the experts were accepted. In the final manuscript, 28 Current Practice Point Statements are included.
Mimics of IBD comprise a heterogeneous group of infectious and non-infectious diseases such as diverticular colitis, diversion proctocolitis, vascular disorders, drug-induced injury and immune disorders .
Infections may mimic IBD clinically, given symptoms such as diarrhoea and abdominal pain, endoscopically with erosions and ulcers and histologically, especially in the resolving phase with chronic inflammation and cryptitis. Some infections, in particular lymphogranuloma venereum and syphilis, resemble IBD. Although architectural disturbance and basal plasmacytosis favour IBD, granulomas may be seen in other conditions, such as tuberculosis . Distinction between IBD and infections requires an extensive questionnaire with attention to travel history and sexual history, assessment of extra-intestinal signs and symptoms, endoscopic examination with biopsy sampling and ancillary techniques such as stool cultures, immunohistochemistry or molecular techniques. The last-mentioned have a higher sensitivity and specificity in the detection of the micro-organisms. Table 1 in the Topical Review shows a nice overview of the infections resembling IBD, their clinical and endoscopic features, histological clues and the ancillary tests used to confirm the infection.
Non-infectious mimics comprise a large heterogeneous group of disorders which may be (a) age related, such as monogenic IBD-like disorders in paediatric patients, (b) related to an inflammatory process, e.g. diverticular colitis or vasculitis, or (c) related to iatrogenic causes including drugs, radiation injury, diversion proctocolitis, etc. . Close collaboration between clinicians and the pathologist is essential, as the clinical presentation and the histological features may resemble IBD. Genetic testing is performed in monogenic IBD-like disorders, including primary immunodeficiencies and intestinal epithelial cells. A lot of information on these non-infectious mimics is included in several tables in the manuscript.
In summary, the Topical Review on Clinicopathological Spectrum & Differential Diagnosis of IBD outlines the differential diagnosis of IBD and discusses morphological pointers and ancillary techniques that assist with the distinction between IBD and its mimics. Constant awareness of the wide variety of mimics of IBD and close communication between clinicians and pathologists are essential. In parallel with the multidisciplinary oncological meeting, in which an oncological patient is discussed from the viewpoint of different specialties, a multidisciplinary meeting with a gastroenterologist, surgeon, radiologist, pathologist etc. may significantly improve the health care of the IBD patient. In any case in which the clinical presentation, histology or other investigation does not support a diagnosis of IBD, caution is appropriate to avoid misdiagnosis and inadequate management.
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