Original Article |
Corresponding author: Mohammad Al Qudah ( m.alqudah12@just.edu.jo ) © 2022 Mohammad Al Qudah, Najib Haboubi.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Al Qudah M, Haboubi N (2022) Pitfalls in the reporting of neoplastic and pseudo neoplastic lesions in the colon and rectum. Folia Medica 64(3): 393-400. https://doi.org/10.3897/folmed.64.e68357
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Introduction: Colonic biopsies comprise large portion of pathologists’ daily work. Within various pathological entities, there are histological ranges and variations. Unawareness of all of these variabilities might lead to misdiagnosis by an inexperienced pathologist and, accordingly, to mismanagement.
Aim: The aim of this article was to alert the reporting pathologist to some of the most common and/or important pitfalls in considering a diagnosis of neoplastic conditions of the colon.
Materials and methods: We highlighted main neoplastic pitfalls in colonic biopsies histopathological investigations.
Results: The pitfalls described in this article are the most common problems we encountered according to our experience. Thus, double reporting for difficult cases is highly recommended to avoid problems in reporting such cases.
Conclusions: Pathologist should be fully alert when reporting some of the most common pitfalls.
colonic biopsies, histopathology, neoplasm, pitfalls
Ever since colonoscopies became widely used, the number of colonic biopsies has escalated to form not only a significant part of the general histopathologist’s workload, but also probably the major part of the gastrointestinal pathologist’s burden. Often, these biopsies have such significant diagnostic importance that clinical judgment is now almost totally reliant on the offered histopathological diagnoses. There are, however, some limitations in assessing biopsies in this way, as well as there are some pitfalls which the general pathologist may fall into that could lead to serious mismanagement.
Dysplasia is defined as the premalignant condition characterised by a spectrum of abnormal cytological, architectural, and mutational changes. In the colon and rectum, the terminology was first popularised by Riddell et al. in 1983 when identifying such lesions in inflammatory bowel disease.[
In the presence of inflammation or ulceration, there are often cellular morphological abnormalities resembling low-grade dysplasia; however, they should not be considered as dysplasia unless there is a high-level certainty based on experience. Features of reactive atypia include enlarged and stratified nuclei, along with an increase in mitotic activity. We suggest that in the presence of an inflammatory background, and crucially in the absence of architectural complexity, it is safer to regard the changes as atypia or indefinite for dysplasia rather than low-grade dysplasia. From the practical point of view, it was often the case that a diagnosis of dysplasia triggers a surgical plan for colectomy. The experiences of many centres showed that negative colectomies can be avoided.[
Acute phase radiation and ischemia are two important entities reported to produce enough significant epithelial changes that can be easily mistaken for colonic dysplasia. Mucosal changes in acute phase radiation bowel disease are commonly seen in specimens after short course radiotherapy for pelvic cancer. The histological features of the benign epithelial cells in the radiation field are so atypical that they mimic high-grade dysplasia (Fig.
Ischemic colitis has been reported to create a morphological picture mimicking dysplasia. Zhang et al.[
Adenomas are the most common dysplastic lesions and prime precursors of carcinoma in the colon and rectum. Removal of adenomas reduces the risk of cancer.[
There are various techniques of removing polyps ranging from cold or hot snares and forceps, endoscopic mucosal resection, and endoscopic submucosal dissection. The aim is to remove the entire polyp - preferably in one piece and with clear margins – for the pathologist to accurately assess the biological behaviour. The recurrence rate of benign polyps is between 13.8% within 1 year and 60% within 3 years.[
The histological features of complete removal are the presence of normal colonic epithelium on both sides of the tumorous element and in some techniques hyalinised amorphous material at the base of the specimen.[
The above reporting style enables the pathologist to be more accurate in passing important information to the clinician and ultimately to the patient. This work was subsequently confirmed in a more comprehensive study in 2014 where false positive reporting was found in 18.8% of cases when the tumour biopsies were compared to the definitive resection surgery.[
Pseudo-invasion is classically encountered in solitary or multiple Peutz-Jegher (P-J) polyps. This type of pseudo-invasion is regular, almost symmetrical in terms of the growth of epithelial crypts into the submucosa and is associated with muscular proliferation resembling the characteristic appearance of a tree branch-like structure.[
The crypts in pseudo invasion still retain their ‘cuff’ of normal lamina propria which is not the case in true invasion.
Yantiss et al.[
The muscularis mucosa (MM) is a crucial landmark in assessing invasion in colorectal cancer. Invasion beyond the MM heralds the potential dissemination of the disease by blood, lymphatics, or local extension. Often the biopsy shows invasion beyond the remnant of architecturally disturbed MM into the submucosa, but on occasion the MM is not available for inspection as it is destroyed by the malignant cells. The work of Jeziorska et al.[
It has been customary to bundle lymphatic channel (LI) and blood vessel invasion (VI) into one prognostic parameter as lymphovascular invasion (LVI) (Fig.
There are many staging systems for early cancer (T1) including malignant polyp. Chronologically, the various staging systems appeared in the literature in this sequence: Haggitt 1985, Kudo 1993, Kikuchi 1995, Kitajima 2004, and Ueno 2004.[
In Davenport et al.[
There has been confusion between the Kudo and Kikuchi’s classification ever since the first paper of Kudo was published addressing the staging of T1 invasion into the submucosa. Although there is some overlap, Kudo introduced the term of submucosal invasion (sm). He divided the submucosa into three parts, grading the invasion to the submucosa as sm1, sm2, or sm3. This classification includes the width of the invasion. Kikuchi’s classification is slightly different as it grades the sm1 if the tumour extends to slight submucosal invasion from the muscularis mucosa to the depth of 200 to 300 µm, sm3 stands for carcinoma invasion reaching near, but not involving, the inner surface of muscularis propria, while sm2 symbolises intermediate invasion between sm1 and sm3. Unfortunately, many pathologists, in the absence of MP, started wrongly equating the depth of invasion with millimetres (mm). For example, they erroneously equate sm1 to 1 mm, sm2 to 2 mm, and sm3 to 3 mm. We have shown that the depth of submucosa varies significantly between individuals and even within different areas of the submucosa in the same individual.[
There are cases in which there is atypical stromal proliferation that could mimic sarcomas. These lesions can create significant problems to the inexperienced pathologist, thus leading to unnecessary radical surgery for a completely benign condition. Giovanni et al.[
Immunohistochemical stains show strong positivity for CD34 in the spindle cells especially around blood vessels. IMT, on the other hand, is a myofibroblastic proliferation with dense plasma cells infiltrate and strong positivity for actin. It is important to make a distinction between IFP, which always runs a benign course, and IMT, which can recur locally. FP is characterised by proliferation of vimentin positive bland spindle cells showing low proliferative activity separating the crypts of the lamina propria with variable amount of chronic inflammatory infiltrate (Fig.
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Conflicts of Interest
The authors declare that they have no conflicts of interest.
Author contributions
The authors contributed equally to data collection, case reviewing, and writing of the manuscript.