1st Edition – 2017

This period saw an unprecedented number of review articles in GIT pathology. Hence, this inaugural edition of journal watch concentrates on these reviews.

Surgical Pathology Clinics

The December 2017 issue was in tightly devoted to luminal gastrointestinal tract disease. These articles are amongst the most comprehensive of any review Journal and are therefore recommended to members of the society.

I particularly enjoyed the following four articles

• Practical approach to the flattened duodenal biopsy. Surgical Pathology Clinics 10 (2017) 823–839.
  This is one of the best practical reviews that I have read covering the causes of a coeliac like pattern in a duodenal biopsy. The author (Thomas Smyrk, Mayo clinic) presents a practical approach infused with extensive personal clinical experience. The illustrations and the tables are first rate.
• Immunohistochemical pitfalls – common mistakes in the evaluation of Lynch syndrome. Surgical Pathology Clinics 10 (2017) 977–100.
  This review presents a practical approach to screening for Lynch syndrome and the potential causes for abnormal patterns of staining and explanations for these patterns. There are several nice summary tables in the article.
• The many faces of medication -related injury in the gastrointestinal tract. Surgical Pathology Clinics 10 (2017) 887–908.
  While many of the topics have been recently covered in other review articles, this manuscript is comprehensive, well presented, and covers the evolving field of injury related to immunomodulatory drugs.
• Persistent problems in colorectal cancer reporting. Surgical Pathology Clinics 10 (2017) 961–976.
  This is a well written and practical account of the common issues encountered in colorectal cancer reporting. It covers serosal involvement, mesenteric tumour deposits and acellular mucin in regional lymph nodes. 

Diagnostic Histopathology

The December 2017 issue of this journal was devoted to gastrointestinal and hepatic pathology. The articles are well written and succinct, covering the core elements of the various subjects. The reviews on low-grade appendiceal mucinous neoplasms and vascular disorders of the liver are particularly recommended.

Advances in Anatomic Pathology

Two highly recommended articles appeared in the January 2018 addition of this journal.

• The role of the surgical pathologist in the diagnosis of gastrointestinal polyposis syndromes. Advances in anatomic pathology 2018;25(1):1-13.
  This was written by AGPS member, Christophe Rosty, and is a practical review on the pathologist role in diagnosing gastrointestinal polyposis syndromes.

Christophe’s article could be read in concert with a concurrently published clinical review on the same subject: Hereditary Colorectal Polyposis and Cancer Syndromes: A Primer on Diagnosis and Management Am J Gastroenterol 2017; 112:1509–1525; doi: 10.1038

• An update on the diagnosis, grading and staging of appendiceal mucinous neoplasms. Advances in anatomic pathology 2018;25(1):38-60.
  This is the best review currently available on appendiceal mucinous neoplasms and related pseudomyxoma peritonei. It covers the practical issues of making the diagnosis of low-grade appendiceal mucinous neoplasm and grading peritoneal disease.

Virchows Archive

A series of great reviews (I am biased of course) dealing with inflammatory diseases of the luminal GIT.

Other

Neuroendocrine tumors of the colon and rectum. Dis Colon Rectum 2017; 60: 1018–1021.

This is a nice and brief review of the clinical staging and treatment implications for neuroendocrine tumours found in the colon and rectum. The review includes a nice algorithm predicting prognosis.

NON-REVIEW ARTICLES

1 – Clinical Outcome of Patients with Raised Intraepithelial Lymphocytes with Normal Villous Architecture on Duodenal Biopsy. Digestion 2017;95:288–292.

This was a retrospective review of the outcome of duodenal biopsies with a pattern of intraepithelial lymphocytosis but normal villous architecture from a single centre in Dublin Ireland. 1.8% of 6244 adult patients (youngest 19 years) with a duodenal biopsy display this pattern. >25 intraepithelial lymphocytes /100 epithelial cells was used as the diagnostic threshold 65% at follow-up, with 32% of these eventually diagnosed as coeliac disease. This is higher than previous studies although given that it is unlikely that the one third of patients lost follow-up did not have coeliac disease, the true figure would appear to be closer to 20%. Factors associated with an eventual diagnosis of coeliac disease included female gender and higher intraepithelial lymphocytes count (typically>40/100 epithelial cells).

2 – ‘Head Invasion’ Is Not a Metastasis-Free Condition in Pedunculated T1 Colorectal Carcinomas Based on the Precise Histopathological Assessment. Digestion 2016;94:166–175.

A paper examining the outcome of malignant colorectal polyps. The main interest is the finding of four cases of invasive malignancy confined to the head of a pedunculated polyp (Haggitt level I) that were associated with lymph node metastases. All four cases had high risk features such as poor differentiation and vascular invasion. This paper highlights a situation that the author of this overview has also witnessed several times. That is, invasion into the head of a pedunculated polyp cannot be regarded as innocuous if high risk features are present, in particular poor differentiation, tumour budding or vascular invasion.

3 – The Apoptotic Crypt Abscess- An Underappreciated Histologic Finding in Gastrointestinal Pathology. Am J Clin Pathol December 2017;148:538-544

This paper looks at causes of a relatively common, but to date not formally examined, finding in colonic biopsy specimens. Broadly apoptotic crypt abscesses were defined as “collections of at least three fragments of pleomorphic cellular debris/sloughed viable cells with crypt lumens”. Additional features are described in the paper. The distinction was drawn with neutrophil crypt abscesses which are much more frequently encountered. Common states in which this process is identified include graft vs host disease (GVHD), acute cellular rejection (ACR), autoimmune enteropathy, viral infections such as cytomegalovirus (CMV) enteritis, and injury by certain drug agents such as mofetil. The authors presented evidence that apoptotic crypt abscess is able to be separated from neutrophil crypt abscess.

4 – Lesions of All Types Exist in Colon Polyps of All Sizes. Am J Gastroenterol advance online publication, 12 December 2017; doi: 10.1038/ajg.2017.439

A retrospective review of the pathology of just over 550,000 polyps. 80% were <10mm diameter. Advanced adenoma features (villosity, high grade dysplasia or invasive carcinoma) was found in 0.6% of 1–5 mm polyps and 2.1% of 6–9 mm polyps and 13.4% of polyps ≥10 mm or larger. 25% of all the advanced adenomas were <10mm in size.

This study should prompt caution for those advocating a resect and discard approach to polyps <10mm diameter (although only 1 in 1000 of the polyps<10mm diameter harboured an invasive adenocarcinoma).

5 – Backwash Is Hogwash: The Clinical Significance of Ileitis in Ulcerative Colitis. Am J Gastroenterol 2017; 112:1211–1214; doi: 10.1038/ajg.2017.182.

A critical review of the literature by Rob Odze and colleague on ‘backwash ileitis’. The conclusions are that many of the early descriptions of patients with backwash ileitis actually had Crohn’s disease of the ileum and colon. While true ileitis in patients with UC does exist, it probably has multiple possible causes. Some of these include “drugs (particularly NSAIDs), infections, alcohol, or even bowel preparatory agents”.

The authors propose the term “UC-associated ileitis” be used instead.