This year's assemblage of reviews from the nether regions takes us on an anatomical journey from the anal canal to the appendix (and even into the neo-rectum formed by the distal ileum) in which we encounter conditions that range from ancient (anal fissures) to recently described (check point inhibitor-related colitis). In each contribution new approaches to diagnosis management are highlighted.
Anal fissures, first described in the late 17th century, though common, often go undiagnosed or incorrectly diagnosed. While we as gastroenterologists are ever keen to insert the colonoscope we, all too frequently, skirt by the anal canal as we zoom to the cecum and, in so doing omit a complete rectal and anal examination and miss what truly ails the patient. If we were mindful of the apt description from the earlier part of the last century  of the ability of fissures to cause ‘such extreme pain in the patient like no other with such tiny spatial dimensions,’ we might be more diligent in seeking out these lesions. Current nonsurgical approaches based on the physiology and pharmacology of the internal anal sphincter should spare most from surgery.
At the other extreme of our historical jaunt we find a completely new entity; check-point colitis, a common and, at times challenging side-effect of these drugs that have revolutionized the management of several cancers. Here again, awareness is the bye word. Wang et al. (pp. 25–32) discuss the many intriguing aspects of this new entity; its implications for overall prognosis and the role of the microbiome . Not only can fecal microbiota transplantation prove curative in steroid-resistant cases  but one's baseline microbial fingerprint predicts the response to antiprogramed cell death protein/ligand-1 antibodies .
Dr Shen (pp. 33–40) introduces us to a new sub-sub specialist in gastroenterology and gastrointestinal endoscopy – the inflammatory bowel disease (IBD) interventional endoscopist. He describes an enviable experience with various endoscopic techniques to deal with complications of IBD and of Crohn's disease, in particular, such as strictures, sinuses, fistulae, and cancers. In so doing he is careful to emphasize when this approach is indicated and when it is not and surgery is more appropriate. As for all aspects of interventional endoscopy, experience both cumulative and ongoing is essential and close consultation with surgical and interventional radiological colleagues mandatory.
Continuing the IBD theme and also renewing our preoccupation with our bacterial fellow travelers, Dr.'s Shah and Zezos (pp. 41–47) update us on another reasonably new disease; pouchitis. This all too common entity that complicates the postoperative course of those whose rectum has been replaced by a neo-rectum fashioned from the distal ileum following total procto-colectomy seems to be bacterially driven and responds to antibiotics and probiotics but, interestingly, benefits from fecal microbiota transplantation seem far from impressive in antibiotic-resistant cases .
Every now and then a pathology report on an appendectomy specimen catches us off guard by announcing the presence of a neuroendocrine tumor in the resected organ. What do we do next – embark on a more extensive surgical resection or assume that the original surgery has sufficed? Dr Detry (pp. 48–54) takes us skillfully through the maze that is the nomenclature of these neoplasms and provides a logical and well-reasoned approach to this occasional but perplexing dilemma.
The ‘bottom’ lines – take a history, be aware of context, do not skimp on the rectal and anal examination, consider endoscopic approaches to IBD complications (if you are sufficiently skilled and experienced), know how to risk classify neuroendocrine tumors and remember it all comes down to microbiota in the end!
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1. Peters W. Die Analfissuren. Z ärztl Fortbildung 1920; 17:371–373.
2. Wang Y, Wiesnoski DH, Helmink BA, et al. Fecal microbiota transplantation for refractory immune checkpoint inhibitor-associated colitis. Nat Med 2018; 24:1804–1808.
3. Bernicker EH, Quigley EM. The gut microbiome influences responses to programmed death 1 therapy in Chinese lung cancer patients: the benefits of diversity. J Thorac Oncol 2019; 14:1319–1322.
4. Selvig D, Piceno Y, Terdiman J, et al. Fecal microbiota transplantation in pouchitis: clinical, endoscopic, histologic, and microbiota results from a pilot study. Dig Dis Sci 2019; [epub ahead of print].