Arnold, Christina A.

This review, based on the content of the 2020 US Gastrointestinal Pathology Society’s Rodger Haggitt Lecture, concerns an array of tubular gastrointestinal tract dysplastic or possible “predysplastic lesions” with an almost purely morphologic focus based on our collaborative efforts over the past few years. These processes include esophageal epidermoid metaplasia, Barrett esophagus-associated dysplasia, polypoid gastric dysplastic lesions, small intestinal dysplasia, and the ability of metastases to mimic it, the controversial “serrated epithelial change” encountered in the setting of long-standing ulcerative and Crohn colitis, and recently described anal columnar human papilloma virus-associated neoplasms.

Selective internal radiation therapy with 90Y-TheraSphere or 90Y-SIRSphere is used in the treatment of unresectable hepatic malignancies. To the best of our knowledge, this is the first 90Y-TheraSpheres series. BTG International Canada Inc. provided nonradiated microspheres from the Nordion manufacturer. The histologic processed microspheres were colorless, refractile, polarizable, 20 to 30 μm in diameter, and an occasional internal bulls’-eye seen with the condenser out and an internal cross seen with polarized light. Identical microspheres were identified in 15 hepatectomy specimens from four centers between February 2016 and March 2018. The patients were usually male (male=10, female=5) with a mean age of 59 years. All patients had a prior diagnosis of hepatocellular carcinoma (HCC) and documented 90Y-TheraSphere (mean duration from last deployment=32 wk). All surgical pathology specimens in these 15 patients were reviewed, but the microspheres were only identified in the hepatectomy specimens. During manuscript preparation, one case of 90Y-TheraSpheres gastritis was prospectively identified from a separate patient with a history of HCC and 90Y-TheraSpheres. In conclusion, recognition of 90Y-TheraSpheres is important so that one may consider the possibility of a nearby malignancy and or establish the cause of the background inflammatory or radiation-related injury. These structures can be easy to miss because the subtle morphology is distinct from previously reported 90Y-SIRSphere. Clues to the diagnosis include a history of HCC and background radiation change. We report the characteristic morphology as microspheres that overlap in size with 90Y-SIRSphere, but can be differentiated based on 90Y-TheraSpheres’ colorless appearance with occasional internal bulls’-eyes with the condenser out and an internal cross with polarized light.

Gastric polyps are found in 1% to 4% of patients undergoing gastroscopy. The vast majority are sporadic, but some gastric polyps indicate an underlying syndrome. Gastric polyps can manifest in each of the gastrointestinal polyposis syndromes, including the recently described gastric adenocarcinoma and proximal polyposis of the stomach syndrome. In addition, gastric polyps occur in Lynch syndrome and in a few rare conditions that are not primarily gastrointestinal. While some of these syndromes are clearly associated with an increased risk of gastric cancer, others are not. Interestingly, even in disorders with a well-established risk of gastric cancer, the neoplastic potential and the precursor status of these gastric polyps are not always clear. Although rare, recognition of syndromic gastric polyps is important for individual patient management. These conditions also serve as important models to study gastric homeostasis and gastric tumorigenesis.

Medication injury in the gastrointestinal tract (GIT) is a rapidly evolving topic. Increasing endoscopy together with an ageing population, polypharmacy, and a burgeoning drug industry offer heightened opportunities to observe the unintended side effects of therapeutic ingestants. In this review, we emphasise the most commonly encountered medication injuries involving the GIT, as well as emerging agents and mimics. While topics are organised by organ system, the reader should keep in mind that injury patterns are generally not site-specific. As such, awareness of these major morphologic patterns can be translated to multiple tissue sites to more broadly facilitate the diagnostic process.