Challenging diagnostic issues in adenomatous polyps with epithelial misplacement in bowel cancer screening: 5 years’ experience of the Bowel Cancer Screening Programme Expert Board

Lymph node metastases and recurrence in pT1 colorectal cancer: Prediction with the International Budding Consortium Score-A retrospective, multi-centric study

BACKGROUND

The International Collaboration on Cancer Reporting proposes histological tumour type, lymphovascular invasion, tumour grade, perineural invasion, extent, and dimensions of invasion as risk factors for lymph node metastases and tumour progression in completely endoscopically resected pT1 colorectal cancer (CRC).

OBJECTIVE

The aim of the study was to propose a predictive and reliable score to optimise the clinical management of endoscopically resected pT1 CRC patients.

METHODS

This multi-centric, retrospective International Budding Consortium (IBC) study included an international pT1 CRC cohort of 565 patients. All cases were reviewed by eight expert gastrointestinal pathologists. All risk factors were reported according to international guidelines. Tumour budding and immune response (CD8+ T-cells) were assessed with automated models using artificial intelligence. We used the information on risk factors and least absolute shrinkage and selection operator logistic regression to develop a prediction model and generate a score to predict the occurrence of lymph node metastasis or cancer recurrence.

RESULTS

The IBC prediction score included the following parameters: lymphovascular invasion, tumour buds, infiltration depth and tumour grade. The score has an acceptable discrimination power (area under the curve of 0.68 [95% confidence intervals (CI) 0.61-0.75]; 0.64 [95% CI 0.57-0.71] after internal validation). At a cut-off of 6.8 points to discriminate high-and low-risk patients, the score had a sensitivity and specificity of 0.9 [95% CI 0.8-0.95] and 0.26 [95% 0.22, 0.3], respectively.

CONCLUSION

The IBC score is based on well-established risk factors and is a promising tool with clinical utility to support the management of pT1 CRC patients.

Incidental findings in the bowel cancer population screening program: other polyps and malignancies - A nationwide study

The introduction of bowel cancer population screening programs has had a profound impact on gastrointestinal pathology. While the focus is mainly on quality assurance of diagnoses relevant for the outcome of these programs (colorectal cancer and its precursors), incidental findings are increasingly diagnosed. The incidence of such findings is largely unknown. Therefore, we investigated the incidence of incidental findings within the national screening program of the Netherlands. From the Dutch nationwide pathology databank (PALGA), we retrieved all histological diagnoses of patients participating in the national bowel cancer screening program from the start in 2014 until 1/1/2021. Descriptive statistics were used. During these 7 years, in total 9407 other polyps and malignancies (262 per 10,000 colonoscopies) were diagnosed. The majority (65%) were classified as inflammatory polyps. The most common malignancies were neuroendocrine tumours (n = 198, 6 per 10,000 colonoscopies); less common were lymphomas (n = 64) and metastases (n = 33). Mesenchymal polyps, such as leiomyomas and lipomas, were relatively common (27 and 16 per 10,000 colonoscopies, respectively), in comparison with neural polyps such as perineuriomas, ganglioneuromas, and neurofibromas (respectively 3, 2, and 1 per 10,000 colonoscopies). This is the largest study into the incidence of nonconventional colorectal polyps and malignancies in a homogeneous cohort of asymptomatic patients. Several of these diagnoses may have consequences for treatment and follow-up, in particular the malignancies and detection of patients with hereditary cancer syndromes.

Rectal tubular adenoma with submucosal pseudoinvasion misdiagnosed as adenocarcinoma: A case report

BACKGROUND

Differential diagnosis of colorectal intramucosal tumors from invasive adenocarcinoma is important in clinical practice due to the different risks of lymph node metastasis and different treatment options. The phenomenon of a colorectal adenoma with part of the gland entering the submucosa is known as pseudoinvasion of the adenoma, which is a major challenge for pathological diagnosis. It is essential to raise awareness of colorectal adenoma with submucosal pseudoinvasion clinically to avoid overtreatment.

CASE SUMMARY

We describe a case of rectal adenoma with submucosal pseudoinvasion in a 48-year-old man. The patient was admitted to Jinhua People's Hospital due to a change in stool habit for 5 d. We performed colonoscopy, and the results suggested a submucosal bulge approximately 1.0 cm × 1.0 cm in size in the rectum 8 cm from the anal verge, with red surface erosion. Ultrasound colonoscopy was also performed and a homogeneous hypoechoic mass about 0.52 cm × 0.72 cm in size was seen at the lesion, protruding into the lumen with clear borders and invading the submucosa. Endoscopic surgery was then performed and the pathological specimen showed a tubular adenoma with high-grade intraepithelial neoplasia (intramucosal carcinoma) involving the adenolymphatic complex. In addition, we performed a literature review of rectal tubular adenoma with submucosal pseudoinvasion to obtain a deeper understanding of this disease.

CONCLUSION

The aim of this study was to improve awareness of this lesion for clinicians and pathologists to reduce misdiagnosis.

Clinical utility of GI pathology data: implications for practising pathologists

Gastrointestinal (GI) tract pathology represents one of the largest individual specialties within cellular pathology departments globally. As with other specialties, clear communication with clinicians providing primary care for the patient is of utmost importance for optimal management and for appropriate use of resources such as endoscopy. A wide breadth of neoplastic and inflammatory conditions afflicts the GI tract. Here, we aim to illustrate how pathology reporting of GI tract specimens influences patient management and specifically how precise reporting of key parameters in different specimen types and different disease processes can directly impact patient care. We describe the potential clinical relevance of selected pathology data items pertinent to specific conditions and highlight areas of contention with respect to the significance of some pathology features. Recent guidelines are described where a change, for example, in diagnostic criteria for a condition is described, or criteria influencing further management such as endoscopic surveillance. The aim of this review is to focus on the clinical importance of careful written communication between the pathologist and primary clinician, illustrated by selective clinical scenarios involving the upper and lower GI tracts.

Pitfalls in the reporting of neoplastic and pseudo neoplastic lesions in the colon and rectum

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.

Infrared Spectroscopic Analysis in the Differentiation of Epithelial Misplacement From Adenocarcinoma in Sigmoid Colonic Adenomatous Polyps

Purpose

The differential diagnosis of epithelial misplacement from invasive cancer in the colon is a challenging endeavour, augmented by the introduction of bowel cancer population screening. The main aim of the work is to test, as a proof-of concept study, the ability of the infrared spectroscopic imaging approach to differentiate epithelial misplacement from adenocarcinoma in sigmoid colonic adenomatous polyps.

Methods

Ten samples from each of the four diagnostic groups, normal colonic mucosa, adenomatous polyps with low grade dysplasia, epithelial misplacement in adenomatous polyps and adenocarcinoma, were analysed using IR spectroscopic imaging and data processing methods. IR spectral images were subjected to data pre-processing and cluster analysis based segmentation to identify epithelial, connective tissue and stromal regions. Statistical analysis was carried out using principal component analysis and linear discriminant analysis based cross validation, to classify spectral features according to the pathology, and the diagnostic attributes were compared.

Results

The combined 4-group classification model on an average showed a sensitivity of 64%, a specificity of 88% and an accuracy of 76% for prediction based on a 'single spectrum', whilst a 'majority-vote' prediction on an average showed a sensitivity of 73%, a specificity of 90% and an accuracy of 82%. The 2-group model, for the differential diagnosis of epithelial misplacement versus adenocarcinoma, showed an average sensitivity and specificity of 82.5% for prediction based on a 'single spectrum' whilst a 'majority-vote' classification showed an average sensitivity and specificity of 90%. A 92% area under the curve (AUC) value was obtained when evaluating the classifier using the Receiver Operating Characteristics (ROC) curves.

Conclusions

IR spectroscopy shows promise in its ability to differentiate epithelial misplacement from adenocarcinoma in tissue sections, considered as one of the most challenging endeavours in population-wide diagnostic histopathology. Further studies with larger series, including cases with challenging diagnostic features are required to ascertain the capability of this modern digital pathology approach. In the long-term, IR spectroscopy based pathology which is relatively low-cost and rapid, could be a promising endeavour to consider for integration into the existing histopathology pathway, in particular for population based screening programmes where large number of samples are scrutinised.

The bowel cancer screening programme expert board - an analysis of activity during 2017-2020

AIMS

The inception of the NHS Bowel Cancer Screening Programme (BCSP) in England in 2006 highlighted that the differential diagnosis between the presence of epithelial misplacement and adenocarcinoma occurring in colorectal adenomas is problematic. The Pathology Expert Board (EB) was created to facilitate review of difficult cases by a panel of three experienced gastrointestinal pathologists. This script describes a review of the work of the EB over a 4-year period (2017-2020).

METHODS & RESULTS

430 polyps were referred to the EB from 193 pathologists and 76 hospitals during this time. The EB diagnosis was benign in 67%, malignant in 28% and equivocal in 2% (with no consensus in the remainder). The most common diagnosis change made by the EB was from malignant to benign - made in 50% of polyps referred with an initially malignant diagnosis. The level of agreement between the individual EB members was 'good' (kappa score 0.619) but that between the EB and the referring diagnosis was 'poor' (kappa score 0.149). Data from one EB member indicated that the presence of lamina propria, features of torsion and cytological similarity between the superficial and deep glands were predictors of a benign diagnosis, while the presence of irregular neoplastic glands, a desmoplastic reaction and lymphovascular invasion were commonly observed features in a malignant diagnosis.

CONCLUSION

Diagnostic agreement between EB members is better than that between the EB and referring pathologists. There was a consistent trend for the EB to change diagnoses from malignant to benign.

Invasive carcinoma versus pseudoinvasion: interobserver variability in the assessment of left-sided colorectal polypectomies

OBJECTIVES

Misplaced epithelium in adenomas can occasionally be difficult to distinguish from invasive adenocarcinoma. We evaluated interobserver variability in the assessment of left-sided colon polypectomies for pseudoinvasion versus invasive adenocarcinoma and further investigated relevant histological findings.

METHODS

28 consecutive left-sided colon polyps with the keywords "pseudoinvasion", "epithelial misplacement", "herniation", "prolapse" or "invasive adenocarcinoma" were collected from 28 patients and reviewed by eight gastrointestinal pathologists. Participants assessed stromal hemosiderin, lamina propria/eosinophils surrounding glands, desmoplasia, high grade dysplasia/intramucosal adenocarcinoma and margin status and rendered a diagnosis of pseudoinvasion, invasive adenocarcinoma, or both.

RESULTS

Agreement among pathologists was substantial for desmoplasia (κ=0.70), high grade dysplasia/intramucosal adenocarcinoma (κ=0.66), invasive adenocarcinoma (κ=0.63) and adenocarcinoma at the margin (κ=0.65). There was moderate agreement for hemosiderin in stroma (κ=0.53) and prolapse/pseudoinvasion (κ=0.50). Agreement was low for lamina propria/eosinophils around glands (κ=0.12). For invasive adenocarcinoma, seven or more pathologists agreed in 24 of 28 cases (86%), and there was perfect agreement in 19/28 cases (68%). For pseudoinvasion, seven or more pathologists agreed in 19 of 28 cases (68%), and there was perfect agreement in 16/28 cases (57%).

CONCLUSION

Moderate to substantial, though imperfect, agreement was achieved in the distinction of pseudoinvasion from invasive carcinoma.

Expression of Extracellular Matrix-Related Genes and Their Regulatory microRNAs in Problematic Colorectal Polyps

Colorectal carcinoma usually evolves gradually, forming a spectrum of lesions, due to accumulation of genetic mutations and epigenetic alterations. Many early lesions are detected since the introduction of screening programs. The greatest challenge is to distinguish between adenomas with epithelial misplacement (AEM) and adenomas with early carcinoma (AEC), considering the diagnosis affects prognosis and treatment. We analyzed the expression of selected extracellular matrix (ECM)-related genes and proteins, and their regulatory microRNAs using RT-qPCR and immunohistochemistry in biopsies from 44 patients. Differences were observed in AEM in comparison to AEC for DCN, EPHA4, FN1, SPON2, and SPP1, reflecting inflammatory stromal reaction to traumatisation and misplacement of dysplastic glands in the submucosa in the former, and desmoplastic stromal reaction to true invasion of dysplastic glands in the submucosa in the latter. Expression of regulatory microRNAs hsa-miR-200c and hsa-miR-146a significantly negatively correlated with the expression of their regulated genes, while significant difference between AEM and AEC was observed only for hsa-miR-29c. The described expression patterns are too complex to be used in diagnostic work, but might contribute to better understanding ECM changes in colorectal carcinoma development, helping to find new markers in the future.

Perianal Paget's disease as spread from non-invasive colorectal adenomas

AIMS

Paget's disease of the perianal skin is a rare form of extramammary Paget's disease, and may be a primary intraepithelial adnexal neoplasm or secondary due to spread from an underlying colorectal lesion, nearly always colorectal adenocarcinoma. Secondary perianal Paget's disease associated with non-invasive colorectal adenomas is exceedingly uncommon, with only a few reported cases.

METHODS AND RESULTS

Herein, we present the clinical and pathological features of the largest series of secondary perianal Paget's disease arising in association with colorectal adenomas. There was gender parity and the median age was 72 years (range = 68-76 years). In all cases, perianal Paget's disease was associated with colorectal adenomas, including three (75%) conventional tubular adenomas and one (25%) tubulovillous adenoma with serrated foci. All adenomas had high-grade dysplasia and one had intramucosal adenocarcinoma (lamina propria invasion; Tis), but all lacked submucosal invasion. The intraepithelial Paget's cells showed a colorectal phenotype by immunohistochemistry in all cases. At follow-up, two patients had no evidence of disease at 6 and 87 months, one had residual perianal Paget's disease at 8 months and one developed invasive adenocarcinoma of the perianal tissue at 36 months.

CONCLUSIONS

Similar to its mammary analogue, secondary perianal Paget's disease may arise in association with invasive and/or in-situ colorectal lesions. Although the latter is an uncommon presentation of a recognised rare disease, knowledge of this phenomenon is important to forestall overdiagnosis of invasion and potential overtreatment. The clinical course is variable, such that close follow-up is required.

Multidimensional and fuzzy sample entropy (SampEnMF) for quantifying H&E histological images of colorectal cancer

In this study, we propose to use a method based on the combination of sample entropy with multiscale and multidimensional approaches, along with a fuzzy function. The model was applied to quantify and classify H&E histological images of colorectal cancer. The multiscale approach was defined by analysing windows of different sizes and variations in tolerance for determining pattern similarity. The multidimensional strategy was performed by considering each pixel in the colour image as an n-dimensional vector, which was analysed from the Minkowski distance. The fuzzy strategy was a Gaussian function used to verify the pertinence of the distances between windows. The result was a method capable of computing similarities between pixels contained in windows of various sizes, as well as the information present in the colour channels. The power of quantification was tested in a public colorectal image dataset, which was composed of both benign and malignant classes. The results were given as inputs for classifiers of different categories and analysed by applying the k-fold cross-validation and holdout methods. The derived performances indicate that the proposed association was capable of distinguishing the benign and malignant groups, with values that surpassed those results obtained with important techniques available in the Literature. The best performance was an AUC value of 0.983, an important result, mainly when we consider the difficulties of clinical practice for the diagnosis of the colorectal cancer.

Bioinformatics Analysis Reveals Most Prominent Gene Candidates to Distinguish Colorectal Adenoma from Adenocarcinoma

Colorectal cancer (CRC) is one of the leading causes of death by cancer worldwide. Bowel cancer screening programs enable us to detect early lesions and improve the prognosis of patients with CRC. However, they also generate a significant number of problematic polyps, e.g., adenomas with epithelial misplacement (pseudoinvasion) which can mimic early adenocarcinoma. Therefore, biomarkers that would enable us to distinguish between adenoma with epithelial misplacement (pseudoinvasion) and adenoma with early adenocarcinomas (true invasion) are needed. We hypothesized that the former are genetically similar to adenoma and the latter to adenocarcinoma and we used bioinformatics approach to search for candidate genes that might be potentially used to distinguish between the two lesions. We used publicly available data from Gene Expression Omnibus database and we analyzed gene expression profiles of 252 samples of normal mucosa, colorectal adenoma, and carcinoma. In total, we analyzed 122 colorectal adenomas, 59 colorectal carcinomas, and 62 normal mucosa samples. We have identified 16 genes with differential expression in carcinoma compared to adenoma: COL12A1, COL1A2, COL3A1, DCN, PLAU, SPARC, SPON2, SPP1, SULF1, FADS1, G0S2, EPHA4, KIAA1324, L1TD1, PCKS1, and C11orf96. In conclusion, our in silico analysis revealed 16 candidate genes with different expression patterns in adenoma compared to carcinoma, which might be used to discriminate between these two lesions.

Histologic Factors Associated With Need for Surgery in Patients With Pedunculated T1 Colorectal Carcinomas

BACKGROUND & AIMS

Most patients with pedunculated T1 colorectal tumors referred for surgery are not found to have lymph node metastases, and were therefore unnecessarily placed at risk for surgery-associated complications. We aimed to identify histologic factors associated with need for surgery in patients with pedunculated T1 colorectal tumors.

METHODS

We performed a cohort-nested matched case-control study of 708 patients diagnosed with pedunculated T1 colorectal tumors at 13 hospitals in The Netherlands, from January 1, 2000 through December 31, 2014, followed for a median of 44 months (interquartile range, 20-80 months). We identified 37 patients (5.2%) who required surgery (due to lymph node, intramural, or distant metastases). These patients were matched with patients with pedunculated T1 colorectal tumors without a need for surgery (no metastases, controls, n = 111). Blinded pathologists analyzed specimens from each tumor, stained with H&E. We evaluated associations between histologic factors and patient need for surgery using univariable conditional logistic regression analysis. We used multivariable least absolute shrinkage and selection operator (LASSO; an online version of the LASSO model is available at: http://t1crc.com/calculator/) regression to develop models for identification of patients with tumors requiring surgery, and tested the accuracy of our model by projecting our case-control data toward the entire cohort (708 patients). We compared our model with previously developed strategies to identify high-risk tumors: conventional model 1 (based on poor differentiation, lymphovascular invasion, or Haggitt level 4) and conventional model 2 (based on poor differentiation, lymphovascular invasion, Haggitt level 4, or tumor budding).

RESULTS

We identified 5 histologic factors that differentiated cases from controls: lymphovascular invasion, Haggitt level 4 invasion, muscularis mucosae type B (incompletely or completely disrupted), poorly differentiated clusters and tumor budding, which identified patients who required surgery with an area under the curve (AUC) value of 0.83 (95% confidence interval, 0.76-0.90). When we used a clinically plausible predicted probability threshold of ≥4.0%, 67.5% (478 of 708) of patients were predicted to not need surgery. This threshold identified patients who required surgery with 83.8% sensitivity (95% confidence interval, 68.0%-93.8%) and 70.3% specificity (95% confidence interval, 60.9%-78.6%). Conventional models 1 and 2 identified patients who required surgery with lower AUC values (AUC, 0.67; 95% CI, 0.60-0.74; P = .002 and AUC, 0.64; 95% CI, 0.58-0.70; P < .001, respectively) than our LASSO model. When we applied our LASSO model with a predicted probability threshold of ≥4.0%, the percentage of missed cases (tumors mistakenly assigned as low risk) was comparable (6 of 478 [1.3%]) to that of conventional model 1 (4 of 307 [1.3%]) and conventional model 2 (3 of 244 [1.2%]). However, the percentage of patients referred for surgery based on our LASSO model was much lower (32.5%, n = 230) than that for conventional model 1 (56.6%, n = 401) or conventional model 2 (65.5%, n = 464).

CONCLUSIONS

In a cohort-nested matched case-control study of 708 patients with pedunculated T1 colorectal carcinomas, we developed a model based on histologic features of tumors that identifies patients who require surgery (due to high risk of metastasis) with greater accuracy than previous models. Our model might be used to identify patients most likely to benefit from adjuvant surgery.

Problematic Colorectal Polyps: Is It Cancer and What Do I Need to Do About It?

Two issues commonly arise for pathologists reporting adenomatous polyps of the colorectum. Particularly problematic within large sigmoid colonic adenomas is the distinction between benign misplacement of epithelium into the submucosa and invasive malignancy. This distinction requires careful morphologic evaluation of key discriminatory features, assisted only rarely by the application of selected adjunctive immunohistochemistry. Following a diagnosis of adenocarcinoma within a polypectomy or other local excision specimen, systematic assessment is required of features that may indicate the risk of residual local and/or nodal neoplastic disease and inform management decision-making regarding the need for further endoscopic or surgical intervention.

Risk for Incomplete Resection after Macroscopic Radical Endoscopic Resection of T1 Colorectal Cancer: A Multicenter Cohort Study

OBJECTIVES

The decision to perform secondary surgery after endoscopic resection of T1 colorectal cancer (CRC) depends on the risk of lymph node metastasis and the risk of incomplete resection. We aimed to examine the incidence and risk factors for incomplete endoscopic resection of T1 CRC after a macroscopic radical endoscopic resection.

METHODS

Data from patients treated between 2000 and 2014 with macroscopic complete endoscopic resection of T1 CRC were collected from 13 hospitals. Incomplete resection was defined as local recurrence at the polypectomy site during follow-up or malignant tissue in the surgically resected specimen in case secondary surgery was performed. Multivariate regression analysis was performed to analyze factors associated with incomplete resection.

RESULTS

In total, 877 patients with a median follow-up time of 36.5 months (interquartile range 16.0-68.3) were included, in whom secondary surgery was performed in 358 patients (40.8%). Incomplete resection was observed in 30 patients (3.4%; 95% confidence interval (CI) 2.3-4.6%). Incomplete resection rate was 0.7% (95% CI 0-2.1%) in low-risk T1 CRC vs. 4.4% (95% CI 2.7-6.5%) in high-risk T1 CRC (P=0.04). Overall adverse outcome rate (incomplete resection or metastasis) was 2.1% (95% CI 0-5.0%) in low-risk T1 CRC vs. 11.7% (95% CI 8.8-14.6%) in high-risk T1 CRC (P=0.001). Piecemeal resection (adjusted odds ratio 2.60; 95% CI 1.20-5.61, P=0.02) and non-pedunculated morphology (adjusted odds ratio 2.18; 95% CI 1.01-4.70, P=0.05) were independent risk factors for incomplete resection. Among patients in whom no additional surgery was performed, who developed recurrent cancer, 41.7% (95% CI 20.8-62.5%) died as a result of recurrent cancer.

CONCLUSIONS

In the absence of histological high-risk factors, a 'wait-and-see' policy with limited follow-up is justified. Piecemeal resection and non-pedunculated morphology are independent risk factors for incomplete endoscopic resection of T1 CRC.