This edition of Pathology Case Reviews examines gastrointestinal polyps throughout the gastrointestinal tract, from the esophagus through the colon. Gastrointestinal polyps represent one of the most common gastrointestinal tissue specimens for many pathology practices. The majority of these lesions are relatively straightforward; however, a number can present diagnostic challenges. Some of these challenges are a function of the rarity of the lesion, whereas others are secondary to confusion regarding terminology. Pathologic examination of gastrointestinal polyps also requires understanding innovations in molecular medicine and medical decision analysis, which can lead to further confusion.
Similar to other areas of pathology, the correlation and communication between pathologists and their clinical colleagues is paramount to make the correct diagnosis and lead to the appropriate clinical management. The majority of gastrointestinal polyps are initially diagnosed by endoscopy and biopsy. Gastroenterologists perform the endoscopy and do the initial gross examination. The information from the endoscopic examination is a very important component of the overall evaluation and needs to be communicated to the pathologist. Often, this is done via the pathology request sheet, but obtaining the original endoscopy report with associated images can be invaluable. It is important for pathologists to feel comfortable with the evaluation of endoscopic images and the limitations of endoscopic evaluation. In addition, understanding of different endoscopic tissue acquisition techniques is also very important to the evaluation of the variety of specimens. Endoscopic biopsy with pinch forceps is the method by which most pathologists receive the majority of biopsy specimens from the gastrointestinal tract. These biopsy forceps come in different sizes (pediatric, standard, and jumbo), all of which typically will obtain a full-thickness biopsy of the mucosa (similar depth) with a different amount of surface (length). Some gastroenterologists will use biopsy forceps with electrocautery (“hot biopsy”), which can cause additional artifacts. Many polyps/polypoid lesions are resected using a variety of techniques including snare polypectomy with or without submucosal injection, endoscopic mucosal resection, and endoscopic submucosal resection. These resection techniques typically extend into the submucosa and should not resect muscularis propria (if one truly sees muscularis propria, this is worthy of a telephone call to the endoscopist). Most of these resection techniques require the pathologist to orient the specimen and evaluate the margins of resection. Orientation is usually able to be done at the gross suite; however, the endoscopist can help with this by inking or pinning out the specimen in the endoscopy suite.
In this issue, we present five case studies and two review articles, by recognized experts in the field of gastrointestinal pathology and gastroenterology, which typify many of the considerations addressed in this editorial. Drs Gunung and Owen present a case of a benign giant fibrovascular polyp of the esophagus. This case shows the importance of communication of the pathologist, radiologist, gastroenterologist, and surgeon in both the diagnosis and appropriate treatment of large gastrointestinal polyps. Dr Sun’s group presents a case of gastric adenoma and highlights the variety of adenoma subtypes, including some recently described less common subtypes, along with their clinical significance. Both Dr Holloman’s and Dr Samowitz’s groups tackle the issue of polyposis in the gastrointestinal tract. Dr Holloman discusses the more common Peutz-Jeghers syndrome, the issue of its mimicry of invasive adenocarcinoma, and the genetic abnormalities and difficult recommendations with respect to surveillance and management. Dr Samowitz describes a very unusual polyposis case ofconstitutional mismatch repair-deficiency syndrome. This case highlights the diagnostic difficulties that may be encountered in both immunohistochemical and molecular analysis of these types of lesions. Dr Yantiss presents a case of sessile serrated polyp (adenoma), a difficult issue at the forefront of the minds of many pathologists who diagnose colonic polyps. Even the terminology of these lesions is not consistent either in the literature or in clinical use, with both sessile serrated polyp and sessile serrated adenoma in use. Her group eloquently reviews the histologic, molecular, and clinical features of these lesions. Two review articles are also presented. Dr Goldblum’s group provides a review of the benign mesenchymal polyps often encountered during routine endoscopic evaluations. Although a less common biopsy specimen than the typical epithelial proliferation, these lesions are often more difficult to diagnose. Dr Wallace is a gastroenterologist with extensive experience and research in the use of advanced endoscopic technologies to provide an “optical biopsy (or in vivo diagnosis).” He reviews the various technologies that could be used for optical biopsy. Many of these techniques (specifically confocal laser endomicroscopy and optical coherence tomography) provide images that mimic standard histologic appearance of the tissue. Pathologists are the natural individuals to interpret these images; however, pathologists must be involved with the implementation of these new techniques.
We hope that you find the cases and reviews interesting, informative, and helpful in improving your clinical practice of gastrointestinal surgical pathology.