Algorithmic Approach to Inflammatory Disorders of Ileum

The ileum undergoes endoscopic biopsy much more than before. Most of these biopsies are either completely normal or show non-specific changes. Nevertheless, in some diseases, ileal biopsy is diagnostic, and in some cases it may be the only anatomical location of the disease. Endoscopically normal mucosal biopsy is unlikely to provide useful diagnostic information and is not routinely recommended. However, in the presence of ileitis, ulcers, or erosions, biopsies can be very helpful. Ileitis might be induced by various conditions including infectious diseases, vasculitis, medication-induced, ischemia, eosinophilic enteritis, tumors etc. The conclusive cause of the condition is proposed by a comprehensive clinical background and physical examination, laboratory investigations, ileocolonoscopy, and imaging findings. Ileoscopy and biopsy are mainly useful in correctly selected cases such as patients that present with inflammatory diarrhea and endoscopic lesions. This review is meant to provide a simple algorithmic approach to the ileal biopsy samples. There are several boxes that give diagnostic clues and an idea behind the categories of ileal disorders.This review is based on the reviewed literature and the authors' experiences. We have summarized different histological patterns in the ileal biopsy specimens that can be used in the diagnosis of inflammatory disorders of the ileum.This review provides an algorithmic approach to the clinicopathological features of inflammatory disorders of the ileum with a brief discussion of some important related issues.