DNA flow cytometric and interobserver study of crypt cell atypia in inflammatory bowel disease

Inflammatory bowel disease-associated serrated lesions with dysplasia are frequently associated with advanced neoplasia: supporting a unified classification approach

AIMS

Inflammatory bowel disease (IBD)-associated serrated lesions are categorized into three distinct subtypes: traditional serrated adenoma (TSA)-like lesion, sessile serrated lesion (SSL)-like lesion, and serrated lesion, not otherwise specified (NOS). Although the risk of neoplastic progression of serrated lesions without dysplasia has not been shown to exceed that of sporadic cases, the clinicopathologic features of the three serrated subtypes with dysplasia remain poorly understood in the context of IBD.

METHODS AND RESULTS

We analysed 87 serrated lesions with dysplasia (collectively referred to as serrated dysplasia) identified endoscopically in 58 IBD patients, including 51 (59%) TSA-like dysplasia, 24 (28%) SSL-like dysplasia, and 12 (14%) serrated dysplasia NOS. Inclusion criteria required all three serrated subtypes to show morphologic evidence of dysplasia and to be located within areas of colitis. We also compared the clinicopathologic features of serrated dysplasia with those of 239 conventional (adenomatous) dysplastic lesions from 149 IBD patients. The cohort included 39 (67%) men and 19 (33%) women, with a mean age of 54 years and a mean IBD duration of 20 years. Most patients had ulcerative colitis (n = 41; 71%) and pancolitis (n = 48; 83%). The majority of serrated lesions with dysplasia had a polypoid or visible endoscopic appearance (n = 73; 84%), with a mean size of 1.4 cm, and were found in the left colon (n = 66; 76%). Most lesions (n = 73; 84%) demonstrated low-grade dysplasia at the time of biopsy diagnosis, whereas high-grade dysplasia (HGD) was identified in the remaining 14 (16%) lesions. SSL-like dysplasia was more frequently associated with ulcerative colitis (94%) compared to TSA-like dysplasia (67%) and serrated dysplasia NOS (56%) (P = 0.042). Although only seven (12%) patients had a concurrent history of primary sclerosing cholangitis, it was exclusively identified in the TSA-like dysplasia group (19% versus 0% in both the SSL-like dysplasia group and the serrated dysplasia NOS group; P = 0.017). Serrated dysplasia NOS more commonly demonstrated HGD at the time of biopsy diagnosis (42%) compared to TSA-like dysplasia (12%) and SSL-like dysplasia (13%) (P = 0.022). Serrated dysplasia NOS was also more frequently associated with synchronous and/or metachronous nonconventional dysplasia (60%) compared to TSA-like dysplasia (16%) and SSL-like dysplasia (9%) (P = 0.037). Serrated dysplasia, regardless of subtype, was associated with high rates of advanced neoplasia (HGD or colorectal cancer) at the previous biopsy site or in the same colonic segment during follow-up. Within a mean follow-up time of 13 months, advanced neoplasia was detected in 50% of the TSA-like dysplasia group, 67% of the SSL-like dysplasia group, and 100% of the serrated dysplasia NOS group (P = 0.622). Moreover, at least one-third of patients in each group (58% in the TSA-like dysplasia group, 44% in the SSL-like dysplasia group, and 33% in the serrated dysplasia NOS group; P = 0.332) developed synchronous/metachronous dysplasia, with at least 50% of these lesions progressing to advanced neoplasia within a mean follow-up time of 11 months (P = 1.000). The serrated dysplasia group showed nearly six times the incidence of advanced neoplasia upon follow-up (59%) compared to the conventional dysplasia group (10%) (P < 0.001).

CONCLUSION

TSA-like dysplasia, SSL-like dysplasia, and serrated dysplasia NOS show distinct clinicopathologic features. However, all three serrated subtypes were associated with high rates of advanced neoplasia (50%-100%) during follow-up, suggesting that these lesions could potentially be combined into one diagnostic category, such as serrated dysplasia.

Dysplasia in Pediatric Patients with Inflammatory Bowel Disease Shows Distinct Clinicopathologic Features Compared to that in Adult Patients

Due to its rarity, there is limited information on the clinicopathologic features of dysplasia in pediatric patients with inflammatory bowel disease (IBD). The existing surveillance guidelines for these patients do not include dysplasia as a potential risk factor for colorectal cancer (CRC), and there is no clear guidance on the optimal strategy for detecting dysplasia. As such, we analyzed the clinicopathologic features of 20 IBD patients who developed at least one instance of dysplasia (n = 56) before the age of 21 years. The results were then compared with data from a previously published adult cohort, which included 315 dysplastic lesions from 167 consecutive adult IBD patients. The study group consisted of 11 males and 9 females, with a mean age of 11 years at the time of IBD diagnosis. The mean age at the time of the first dysplasia diagnosis was 18 years for the study group compared to 54 years for the adult group. The study group had a lower incidence of ulcerative colitis (65% vs. 92% in the adult group, p < 0.001), but the proportion of patients with concurrent primary sclerosing cholangitis (PSC) was nearly double that of the adult group (25% vs. 13%, p = 0.129). Dysplasia in the study group was more likely to be nonconventional (38%, p = 0.047) and invisible or flat (50%, p < 0.001) compared to the adult group (25% and 24%, respectively). High-risk nonconventional dysplastic subtypes, including crypt dysplasia (13%, p = 0.016), goblet cell-deficient dysplasia (11%, p = 0.010), and hypermucinous dysplasia (9%, p = 0.009), were more common in the study group compared to the adult group (4%, 3%, and 2%, respectively). The mean duration from IBD diagnosis to the first dysplasia diagnosis was significantly shorter in the study group (8 years) than in the adult group (16 years) (p = 0.005). While dysplastic lesions in the adult group were more likely to present as high-grade dysplasia (HGD) at initial diagnosis (17% vs. 4% in the study group, p = 0.008), the rate of advanced neoplasia (HGD or CRC) on follow-up was similar between the two groups (26% in the adult group vs. 22% in the study group, p = 1.000). In conclusion, dysplasia in pediatric IBD patients is often associated with nonconventional features (including the high-risk subtypes), an invisible/flat appearance, concurrent PSC, and early development (within 8 years of IBD diagnosis).

Examination of non-conventional dysplasias adjacent to colorectal adenocarcinoma in patients with IBD

Objective

Recently, several non-conventional variants of IBD-associated dysplasia have been described; however, their prevalence in Central-Eastern Europe is unknown. We aimed to perform a retrospective pilot study by re-evaluating several IBD-associated adenocarcinoma cases to survey the incidence of adjacent non-conventional dysplasia and validate that recent North American findings may apply to a European population.

Methods

Retrospectively, 28 randomly chosen cases of IBD-associated adenocarcinomas diagnosed between 2010 and 2022 were re-evaluated. The patient's sex, age (at the diagnosis of IBD and neoplasia), type of IBD, type of specimen [biopsy (n = 8)/surgical specimen (n = 20)], histological type, grade, localisation, stage, disease-free (DFS) and overall survival (OS) were obtained. Statistical analyses were carried out by using Mann-Whitney (continuous variables), Fisher's exact (categorical variables), Kaplan-Meier (DFS/OS curves), and logrank test (survival curves).

Results

Exclusively, conventional dysplasia was observed in 11, and non-conventional dysplasia in 8 patients. Combined conventional and non-conventional dysplasia was detected in 9 patients. Non-conventional dysplasia showing a combination of multiple subtypes was noted in 10 cases. Altogether, 25 non-conventional dysplastic foci were identified, which were diagnosed as hypermucinous (n = 9), goblet cell-deficient (n = 6), serrated not otherwise specified (NOS) (n = 6), and traditional serrated adenoma-like (n = 4). The majority of non-conventional dysplasias were associated with ulcerative colitis (n = 12). Mucinous adenocarcinoma was exclusively associated with non-conventional dysplasia, while medullary carcinoma was only with conventional dysplasias (p = 0.014 and 0.041).

Conclusion

Based on our results, non-conventional dysplasia is common (60%) adjacent to IBD-associated adenocarcinomas in a Central-Eastern European population and may be detected in biopsies. As multiple recent publications reported evidence of a worse prognosis and more common flat morphology compared to conventional dysplasias, their recognition is of great importance, and stricter follow-up with random biopsy samples may be considered.

Dysplasia Detected in Patients With Serrated Epithelial Change Is Frequently Associated With an Invisible or Flat Endoscopic Appearance, Nonconventional Dysplastic Features, and Advanced Neoplasia

The significance of serrated epithelial change (SEC), defined as endoscopically invisible hyperplastic polyp (HP)-like mucosal change identified in patients with inflammatory bowel disease (IBD), remains unclear. Although some studies reported an increased risk of synchronous and/or metachronous colorectal neoplasia in patients with SEC, including advanced neoplasia (high-grade dysplasia or colorectal cancer), the development of SEC is not significantly associated with increased colonic inflammation. This contrasts with the reported positive correlation between increased colonic inflammation and the risk of colorectal neoplasia in ulcerative colitis, arguing against the notion that SEC may represent a form of dysplasia. As such, this study aimed to characterize the features of synchronous and metachronous dysplasia detected in patients with SEC to identify factors contributing to the increased risk of colorectal neoplasia, including advanced neoplasia, observed in a subset of these patients. Clinicopathologic features of 46 IBD patients with SEC (n=109) and synchronous and/or metachronous dysplasia (n=153) were analyzed. All dysplastic lesions were subtyped as either conventional or nonconventional dysplasia. As controls, 45 IBD patients with endoscopically visible or polypoid HP (n=75) and synchronous and/or metachronous dysplasia (n=87) were analyzed. The SEC group included 28 (61%) men and 18 (39%) women with a mean age of 58 years and a long history of IBD (mean duration: 23 years). The majority of patients (n=34; 74%) had ulcerative colitis, and 12 (26%) had Crohn's disease. Thirty-nine (85%) patients had a history of pancolitis, and 2 (4%) had concomitant primary sclerosing cholangitis. Twenty-seven (59%) patients had multifocal SEC. SEC was predominantly found in the left colon (n=52; 48%) and rectum (n=34; 31%). Dysplasia in the SEC group was often endoscopically invisible or flat (n=42; 27%) and demonstrated nonconventional dysplastic features (n=49; 32%). Six nonconventional subtypes were identified in the SEC group, including 17 (11%) dysplasia with increased Paneth cell differentiation, 12 (8%) hypermucinous dysplasia, 8 (5%) crypt cell dysplasia, 7 (5%) goblet cell deficient dysplasia, 3 (2%) sessile serrated lesion-like dysplasia, and 2 (1%) traditional serrated adenoma-like dysplasia. Advanced neoplasia was detected in 11 (24%) patients. The SEC group was more likely to have nonconventional dysplasia (32%, P <0.001), invisible/flat dysplasia (27%, P <0.001), and advanced neoplasia (24%, P <0.001) than the control group (7%, 2%, and 0%, respectively). High-risk nonconventional subtypes (ie, hypermucinous, crypt cell, and goblet cell deficient dysplasias) accounted for 18% of all dysplastic lesions in the SEC group, which were not seen in the control group ( P <0.001). The SEC group (n=35; 76%) also had a higher rate of concordance between the location of SEC and the area of synchronous/metachronous dysplasia than the control group (n=22; 49%) ( P =0.007). In conclusion, dysplasia detected in patients with SEC is often endoscopically invisible/flat (27%), nonconventional (32%, including the high-risk subtypes), and found in the same colonic segment as SEC (76%), which may in part explain why some patients with SEC are associated with an increased risk of colorectal neoplasia, including advanced neoplasia. The finding of SEC may warrant a careful follow-up colonoscopy with increased random biopsy sampling, especially in the segment of colon with SEC.

Increased Active Inflammation in the Colon is Not a Reliable Predictor of an Elevated Risk of Dysplasia in Patients With Primary Sclerosing Cholangitis and Ulcerative Colitis

Although the increased risk of colorectal neoplasia in patients with both primary sclerosing cholangitis (PSC) and ulcerative colitis (UC; termed PSC-UC) is well documented, the mechanism through which concomitant PSC increases the risk of colorectal neoplasia remains unclear. Given that the risk of colorectal neoplasia in UC is positively correlated with increased histologic inflammation, this study sought to investigate whether increased histologic inflammation could be used to stratify the risk of dysplasia development in patients with PSC-UC. Twenty patients with PSC-UC and dysplasia were compared with 30 control patients with PSC-UC who had no history of neoplasia. For each patient, all surveillance biopsies were scored using a 4-point scoring system: (1) no epithelial neutrophils = 0, (2) cryptitis only = 1, (3) cryptitis plus crypt abscess in <50% of crypts = 2, and (4) crypt abscess in ≥50% of crypts, erosion, neutrophilic exudate, and/or ulceration = 3. A score was designated for each biopsy, and both mean and maximum inflammation scores were calculated from all biopsies taken during each colonoscopy. The inflammation burden score was calculated for each surveillance interval by multiplying the average maximum score between each pair of surveillance episodes by the length of the surveillance interval in years. The average scores derived from all colonoscopies for each patient were used to determine the patient's overall mean, maximum, and inflammation burden scores. In both the dysplasia and control groups, the 3 summative inflammation scores were calculated independently for the entire colon, right colon, and left colon. The dysplasia group consisted of 14 (70%) men and 6 (30%) women, with a mean age of 27 years at UC diagnosis and a long history of pancolitis (mean duration: 17 y). A total of 49 dysplastic lesions were detected in the dysplasia group, and 8 (40%) of the 20 patients had multifocal dysplasia. The majority of dysplastic lesions belonged to nonconventional subtypes (n = 28; 57%) and were located in the right colon (n = 37; 76%). Irrespective of the colon segment, there was no significant difference in the 3 summative inflammation scores between the dysplasia and control groups ( P > 0.05). However, in each group, the 3 summative inflammation scores were significantly higher in the right colon than in the left colon ( P < 0.05). In conclusion, patients with PSC-UC exhibit increased histologic inflammation in the right colon compared with the left colon, regardless of the presence of dysplasia. Although this may provide an explanation for the predominance of right-sided colorectal neoplasia in patients with PSC-UC, increased histologic inflammation does not reliably predict an elevated risk of dysplasia in patients with PSC-UC. These findings reinforce the current recommendation for annual endoscopic surveillance for all patients with PSC-UC, irrespective of the extent and severity of inflammation.

Nonconventional Dysplasia is Frequently Associated With Goblet Cell Deficient and Serrated Variants of Colonic Adenocarcinoma in Inflammatory Bowel Disease

Various subtypes of nonconventional dysplasia have been recently described in inflammatory bowel disease (IBD). We hypothesized that goblet cell deficient dysplasia and serrated dysplasia may be the primary precursor lesions for goblet cell deficient (GCDAC) and serrated (SAC) variants of colonic adenocarcinoma, respectively. Clinicopathologic features of 23 GCDAC and 10 SAC colectomy cases were analyzed. All dysplastic lesions found adjacent to the colorectal cancers (n = 22 for GCDACs and n = 10 for SACs) were subtyped as conventional, nonconventional, or mixed-type dysplasia. As controls, 12 IBD colectomy cases with well to moderately differentiated adenocarcinoma that lacked any mucinous, signet ring cell, low-grade tubuloglandular, or serrated features while retaining goblet cells throughout the tumor (at least 50% of the tumor) were evaluated. The cohort consisted of 19 (58%) men and 14 (42%) women, with a mean age of 53 years and a long history of IBD (mean duration: 18 y). Twenty-seven (82%) patients had ulcerative colitis. GCDACs (57%) were more often flat or invisible than SACs (10%) and controls (25%; P = 0.023). The GCDAC and SAC groups were more likely to show lymphovascular invasion (GCDAC group: 52%, SAC group: 50%, control group: 0%, P = 0.001) and lymph node metastasis (GCDAC group: 39%, SAC group: 50%, control group: 0%, P = 0.009) than the control group. Notably, GCDACs and SACs were more frequently associated with nonconventional dysplasia than controls (GCDAC group: 77%, SAC group: 40%, control group: 0%, P < 0.001). Goblet cell deficient dysplasia (73%) was the most prevalent dysplastic subtype associated with GCDACs ( P = 0.049), whereas dysplasias featuring a serrated component (60%) were most often associated with SACs ( P = 0.001). The GCDAC group (75%) had a higher rate of macroscopically flat or invisible synchronous dysplasia compared with the SAC (20%) and control (33%) groups ( P = 0.045). Synchronous dysplasia demonstrated nonconventional dysplastic features more frequently in the GCDAC (69%) and SAC (40%) groups compared with the control group (0%; P = 0.016). In conclusion, goblet cell deficient dysplasia and dysplasias featuring a serrated component could potentially serve as high-risk markers for GCDACs and SACs, respectively.

Pathology and Clinical Significance of Inflammatory Bowel Disease-Associated Colorectal Dysplastic Lesions

Timely diagnosis and effective management of colorectal dysplasia play a vital role in preventing mortality from colorectal cancer in patients with chronic inflammatory bowel disease. This review provides a contemporary overview of the pathologic and endoscopic classification of dysplasia in inflammatory bowel disease, their roles in determining surveillance and management algorithms, and emerging diagnostic and therapeutic approaches that might further enhance patient management.

Recently described types of dysplasia associated with IBD: tips and clues for the practising pathologist

Longstanding inflammatory bowel disease (especially in patients with severely active disease or primary sclerosing cholangitis) is associated with an increased risk of developing dysplasia and adenocarcinoma. This review covers critical clinical aspects, such as risk factors and screening endoscopy basics, emphasising the SCENIC (Surveillance for Colorectal Endoscopic Neoplasia Detection in Inflammatory Bowel Disease International Consensus) guidelines. The histopathological and molecular features of both conventional (adenomatous) dysplasia and the non-conventional subtypes (hypermucinous dysplasia, goblet cell-deficient dysplasia, crypt cell dysplasia, serrated dysplasias) are discussed with an emphasis on challenging diagnostic areas and helpful tips to allow correct categorisation by the practising pathologist.

Gastric metaplasia as a precursor of nonconventional dysplasia in inflammatory bowel disease

Gastric metaplasia in colonic mucosa with inflammatory bowel disease (IBD) develops as an adaptation mechanism. The association between gastric metaplasia and nonconventional and/or conventional dysplasia as precursors of colitis-associated colorectal cancer is unknown. To address this question, we retrospectively reviewed a series of 33 IBD colectomies to identify gastric metaplasia in 76 precursor lesions. We obtained 61 nonconventional and 15 conventional dysplasias. Among nonconventional dysplasia, 31 (50.8 %) were low-grade (LGD), 4 (6.5 %) were high-grade (HGD), 9 (14.8 %) had both LGD and HGD, and 17 (27.9 %) had no dysplasia (ND), while 14 (93 %) conventional dysplasias had LGD, and 1 (7 %) had LGD and HGD. Gastric metaplasia was assessed by concomitant immunoexpression of MUC5AC and loss of CDX2 staining. Expression of a p53-mut pattern was considered as a surrogate for gene mutation, and complete loss of MLH1 staining as presence of MLH1 hypermethylation. In nonconventional dysplasia, MUC5AC immunoexpression decreased as the degree of dysplasia increased, being 78 % in LGD and 39 % in HGD (p = 0.006). CDX2 was lost in epithelial glands with high expression of MUC5AC (p < 0.001). The p53-mut pattern was observed in 77 % HGD, 45 % LGD, and in 6 % with ND (p < 0.001). Neither nonconventional nor conventional dysplasia showed complete loss of MLH1 staining. Gastric metaplasia was also present in mucosa adjacent to nonconventional dysplasia with chronic changes or active inflammation. Our results show that gastric metaplasia appears in IBD-inflamed colon mucosa, it is the substrate of most nonconventional dysplasia and occurs prior to p53 alterations.

Characteristics, Reporting, and Potential Clinical Significance of Nonconventional Dysplasia in Inflammatory Bowel Disease

The term nonconventional dysplasia has been coined to describe several underrecognized morphologic patterns of epithelial dysplasia in inflammatory bowel disease (IBD), but to date, the full recognition of these newly characterized lesions by pathologists is uneven. The identification of nonconventional dysplastic subtypes is becoming increasingly important, as they often present as invisible/flat dysplasia and are more frequently associated with advanced neoplasia than conventional dysplasia on follow-up. This review describes the morphologic, clinicopathologic, and molecular characteristics of seven nonconventional subtypes known to date, as well as their potential significance in the clinical management of IBD patients.

Colorectal dysplasia in chronic inflammatory bowel disease: a contemporary consensus classification and interobserver study

The clinical management of patients with dysplasia in chronic inflammatory bowel disease (IBD) is currently guided by Riddell et al.'s grading system (negative, indefinite, low grade, high grade) from 1983 which was based primarily on nuclear cytoarchitectural characteristics. Although most dysplasia in IBD resembles sporadic adenomas morphologically, other distinctive potential cancer precursors in IBD have been described over time. Recognizing the need for a updated comprehensive classification for IBD-associated dysplasia, an international working group of pathologists with extensive clinical and research experience in IBD devised a new classification system and assessed its reproducibility by having each participant assess test cases selected randomly from a repository of electronic images of potential cancer precursor lesions. The new classification system now encompasses three broad categories and nine sub-categories: 1) intestinal dysplasia (tubular/villous adenoma-like, goblet cell deficient, crypt cell, traditional serrated adenoma-like, sessile serrated lesion-like and serrated NOS), 2) gastric dysplasia (tubular/villous and serrated), and 3) mixed intestinal-gastric dysplasia. In the interobserver analysis, 67% of the diagnoses were considered definitive and achieved substantial inter-rater agreement. The key distinctions between intestinal and gastric lesions and between serrated and non-serrated lesions achieved substantial and moderate inter-rater agreement overall, respectively, however, the distinctions among certain serrated sub-categories achieved only fair agreement. Based on the Riddell grading system, definite dysplasia accounted for 86% of the collective responses (75% low grade, 11% high grade). Based on these results, this new classification of dysplasia in IBD can provide a sound foundation for future clinical and basic IBD research.

p53 as Exemplar Next-Generation Immunohistochemical Marker: A Molecularly Informed, Pattern-Based Approach, Methodological Considerations, and Pan-Cancer Diagnostic Applications

This review is based on a webinar I presented for the International Society for Immunohistochemistry and Molecular Morphology (ISIMM) in February 2022. It is intended that all ISIMM webinars will ultimately be published in AIMM as review articles. This work is also dedicated to Clive Taylor, who has deeply impacted my career. It presents a molecularly informed, pattern-based approach to p53 immunohistochemistry interpretation, methodological considerations (ie, antibody selection, optimization, validation, controls, and external quality assessment), and pan-cancer diagnostic applications, including those drawn from gastrointestinal, genitourinary, gynecological, neuroendocrine, hematologic, and neuropathology. It intends to prove the thesis statement that p53 is an exemplar next-generation immunohistochemical marker "born" ahead of its time.

[Conventional and non-conventional dysplasia in patients with inflammatory bowel disease]

Compared to the general population, patients with inflammatory bowel disease (IBD), both ulcerative colitis (UC) or Crohn's disease (CD), are at increased risk of developing some cancers, particularly colorectal cancers (CRC). CRCs, the vast majority of which are adenocarcinomas, develop from a precancerous lesion called dysplasia (or intraepithelial neoplasia) via an inflammation-dysplasia-adenocarcinoma sequence. The advancements of new endoscopic techniques, including visualisation and resection techniques, has led to a reclassification of dysplasia lesions into visible and invisible lesions and their therapeutic management, with a more conservative approach to the colorectal setting. In addition, besides conventional dysplasia, of intestinal phenotype, classically described in IBD, non-conventional dysplasias (as opposed to conventional dysplasia of intestinal phenotype) are now described, including at least seven subtypes. Recognition of these unconventional subtypes, which are still poorly known from pathologists, is becoming crucial, as some of these subtypes appear to be at high risk of developing advanced neoplasia (i.e. high-grade dysplasia or CRC). This review briefly describes the macroscopic features of dysplastic lesions in IBD, as well as their therapeutic management, followed by the clinicopathological features of these dysplastic lesions, with particular emphasis on the new subtypes of unconventional dysplasia, both from a morphological and molecular point of view.

Increased Risk of Non-conventional and Invisible Dysplasias in Patients with Primary Sclerosing Cholangitis and Inflammatory Bowel Disease

BACKGROUND AND AIMS

Patients with primary sclerosing cholangitis and inflammatory bowel disease [termed PSC-IBD] have a higher risk of developing colorectal neoplasia than those with IBD alone. The mechanism by which concomitant PSC increases the risk of colorectal neoplasia remains unknown. Seven distinct non-conventional dysplastic subtypes have been recently described in IBD, including crypt cell dysplasia, hypermucinous dysplasia, goblet cell-deficient dysplasia, dysplasia with increased Paneth cell differentiation [DPD], sessile serrated lesion [SSL]-like dysplasia, traditional serrated adenoma [TSA]-like dysplasia, and serrated dysplasia, not otherwise specified [NOS]. Despite the lack of high-grade morphological features, crypt cell, hypermucinous, and goblet cell-deficient dysplasias often show molecular features characteristic of advanced neoplasia [i.e. aneuploidy and KRAS mutations] and are more frequently associated with advanced neoplasia than conventional dysplasia on follow-up. We aimed to characterise clinicopathological features of dysplasia found in PSC-IBD patients.

METHODS

A cohort of 173 PSC-IBD patients were analysed. All dysplastic lesions were subtyped as either conventional or non-conventional dysplasia. The clinicopathological features of PSC-IBD patients with neoplasia were also compared with those of non-PSC IBD patients with neoplasia.

RESULTS

There were 109 [63%] men and 64 [37%] women, with a mean age of 26 years at IBD diagnosis and a long history of IBD [mean duration: 14 years]. Ulcerative colitis was the most common IBD subtype [80%], and the majority of patients [92%] had a history of pancolitis. A total of 153 dysplastic lesions were detected in 54 [31%] patients, 35 [65%] of whom had multifocal dysplasia. One additional patient presented with colorectal cancer [CRC] without a history of dysplasia. Dysplasia was often non-conventional [n = 93; 61%], endoscopically/grossly invisible [n = 101; 66%], and right/proximal-sided [n = 90; 59%]. All seven non-conventional subtypes were identified, including 46 [30%] crypt cell dysplasia, 23 [15%] hypermucinous dysplasia, 12 [8%] goblet cell-deficient dysplasia, seven [5%] DPD, three [2%] TSA-like dysplasia, one [1%] SSL-like dysplasia, and one [1%] serrated dysplasia NOS. Follow-up information was available for 86 lesions, of which 32 [37%] were associated with subsequent detection of advanced neoplasia [high-grade dysplasia or CRC] within a mean follow-up time of 55 months. PSC-IBD patients with neoplasia were more likely to have pancolitis [98%, p = 0.039] and a longer IBD duration [mean: 17 years, p = 0.021] than those without neoplasia [89% and 12 years, respectively]. When compared with a cohort of non-PSC IBD patients with neoplasia, the PSC-IBD group with neoplasia was more often associated with non-conventional [61%, p <0.001], invisible [66%, p <0.001], and right/proximal-sided [59%, p = 0.045] dysplasias [vs 25%, 21%, and 47%, respectively, for the non-PSC IBD group]. The rate of advanced neoplasia was nearly 2-fold higher in the PSC-IBD group [37%] compared with the non-PSC IBD group [22%] [p = 0.035].

CONCLUSIONS

Nearly a third of PSC-IBD patients developed dysplasia, which is often associated with non-conventional dysplastic features, invisible endoscopic/gross appearance, right/proximal-sided colon, multifocality, and advanced neoplasia on follow-up. These findings underscore the importance of recognising these non-conventional subtypes by practising pathologists and the need for careful and frequent endoscopic surveillance, with random biopsies, in PSC-IBD patients.

Increased Histologic Inflammation is an Independent Risk Factor for Non-Conventional Dysplasia in Ulcerative Colitis

AIMS

Several types of non-conventional dysplasia have been described in inflammatory bowel disease. Hypermucinous, goblet cell deficient, and crypt cell dysplasias are considered high-risk subtypes, as they often have molecular features of advanced neoplasia (e.g., aneuploidy) and are more frequently associated with advanced neoplasia than conventional dysplasia. This study investigated if increased colonic inflammation is a risk factor for non-conventional dysplasia.

METHODS AND RESULTS

A cohort of 125 patients with ulcerative colitis (UC)-associated dysplasia were analyzed and compared with 50 control UC patients without a history of neoplasia. For each patient, all biopsies prior to the initial detection of dysplasia were scored using a 4-point inflammatory activity score. Both mean and maximum scores from all biopsies taken during each colonoscopy were derived. Inflammation burden was calculated by multiplying average maximum score between each pair of surveillance episodes by length of surveillance interval in years. The average scores of all colonoscopies were used to calculate overall mean, maximum, and inflammation burden scores. In multivariate analyses, higher maximum (odds ratio [OR] 3.4) and inflammation burden (OR 4.2) scores were significantly associated with the detection of dysplasia (p < 0.05). Similarly, higher mean and maximum scores increased the odds of non-conventional dysplasia by 2.7 and 4.9, respectively (p < 0.05). There was a stronger association between these two scores and high-risk subtypes (ORs 4.0 and 7.5, respectively, p < 0.05).

CONCLUSIONS

The risk of non-conventional dysplasia is significantly associated with increased inflammation, which may contribute to its higher rates of aneuploidy and malignancy.

Clinicopathologic Features of Undetected Dysplasia Found in Total Colectomy or Proctocolectomy Specimens of Patients with Inflammatory Bowel Disease

AIMS

It remains controversial as to whether targeted biopsies should completely replace random biopsies for dysplasia surveillance in patients with inflammatory bowel disease (IBD). Several histologic patterns of non-conventional dysplasia have been described in IBD. This study aimed to investigate the rate and clinicopathologic features of dysplastic lesions found in total colectomy or proctocolectomy specimens that were undetected on prior colonoscopy.

METHODS AND RESULTS

The study analyzed 207 consecutive IBD patients who underwent a total colectomy or proctocolectomy and had at least one high definition colonoscopy prior to colectomy. Dysplasia found in the colectomy specimens was classified as undetected, only when there was no corresponding site of dysplasia detected on previous colonoscopic biopsies. Twenty-seven (13%) patients had 49 undetected dysplastic lesions found only at colectomy, while 22 (11%) had 31 previously detected dysplastic lesions only. The remaining 158 (76%) patients had no dysplasia. A greater proportion of the undetected (19%) or previously detected (23%) dysplasia group had concurrent primary sclerosing cholangitis compared with only 3% in the group without dysplasia (p < 0.001). The undetected dysplastic lesions were more likely to have non-conventional dysplastic features (76%), low-grade dysplasia (94%), and a flat/invisible gross appearance (73%) compared with the previously detected dysplastic lesions (13%, 68%, and 48%, respectively) (p < 0.05). Almost all patients with undetected dysplasia (93%) had a colonoscopy within 1 year of colectomy.

CONCLUSIONS

The rate of undetected dysplasia is not insignificant (13%), suggesting that increased random biopsies may improve the rate of dysplasia detection, including non-conventional dysplasia.

Role of DNA Flow Cytometry in the Diagnosis of Malignancy in Bile Duct Biopsies Using Paraffin-Embedded Tissue

OBJECTIVES

Histopathologic evaluation of bile biopsies for biliary strictures is frequently challenging and is affected by interobserver disagreement. Reliable ancillary tests that can help differentiate benign from malignant are not available. This study aimed to evaluate whether DNA content abnormalities detected by flow cytometry on formalin-fixed, paraffin-embedded (FFPE) tissue can help differentiate benign/reactive, dysplastic from malignant cell populations in bile duct biopsies.

METHODS

We performed DNA flow cytometry on 30 FFPE bile duct biopsies in 5 well-defined diagnostic categories: (1) negative for dysplasia (NED), (2) low-grade dysplasia (LGD), (3) high-grade dysplasia (HGD), (4) carcinoma (CA), and (5) indefinite for dysplasia (IND).

RESULTS

Abnormal DNA content was detected in 0 NED, 5 LGD (62.5%), 2 HGD (33.3%), 3 CA (60%), and 4 IND (80%) samples. As a diagnostic marker, the estimated sensitivity, specificity, positive predictive value, and negative predictive value were 63%, 100%, 100%, and 50%, respectively, for diagnosing HGD or CA.

CONCLUSIONS

DNA flow cytometry analysis is a useful ancillary test for the interpretation of bile duct biopsies. DNA content abnormalities, when correlated with histologic findings, will not only help confirm the morphologic impression but also identify patients who are at a higher risk of developing malignancy.

Hypermucinous, Goblet Cell-Deficient and Crypt Cell Dysplasias in Inflammatory Bowel Disease are Often Associated with Flat/Invisible Endoscopic Appearance and Advanced Neoplasia on Follow-Up

BACKGROUND AND AIMS

Several different types of non-conventional dysplasia have been recently described in inflammatory bowel disease [IBD]. Hypermucinous, goblet cell-deficient and crypt cell dysplasias have received most attention, but there is limited information regarding their clinicopathological features and clinical outcomes.

METHODS

A total of 126 cases of hypermucinous [n = 55], goblet cell-deficient [n = 26] and crypt cell [n = 45] dysplasias from 97 IBD patients were collected from seven different institutions and analysed.

RESULTS

The cohort included 62 [64%] men and 35 [36%] women with a mean age of 49 years [range: 20-78]. The majority of affected patients had longstanding IBD [mean duration: 18 years]. Nineteen [20%] patients had a concurrent history of primary sclerosing cholangitis. As a group, non-conventional dysplasia was predominantly found in patients with ulcerative colitis [UC] [n = 68; 70%] and occurred in the left colon [n = 80; 63%]; however, hypermucinous dysplasia [57%] was the least frequently associated with UC compared with goblet cell-deficient [74%] and crypt cell [89%] dysplasias [p = 0.016]. Fifty [52%] patients had a history of conventional dysplasia, detected in the same colonic segment as non-conventional dysplasia at a rate of 33%. Goblet cell-deficient dysplasia [74%] was more frequently associated with conventional dysplasia than hypermucinous [43%] and crypt cell [48%] dysplasias [p = 0.044]. While hypermucinous dysplasia often had a polypoid appearance [58%], crypt cell [96%] and goblet cell-deficient [65%] dysplasias were more likely to present as flat/invisible lesions [p < 0.001]. Most lesions were low-grade [87%] at diagnosis, but goblet cell-deficient dysplasia [31%] more often showed high-grade dysplasia [HGD] compared with hypermucinous [15%] and crypt cell [0%] dysplasias [p = 0.003]. Hypermucinous dysplasia usually demonstrated a tubulovillous/villous architecture [76%], whereas goblet cell-deficient dysplasia was predominantly tubular [92%]. A flat architecture was exclusively associated with crypt cell dysplasia [100%] [p < 0.001]. Immunohistochemical stain results for p53 were available for 33 lesions; 14 [42%] showed strong [3+] and patchy [10-50%] to diffuse [>50%] nuclear overexpression or null staining pattern, including four [33%] of 12 hypermucinous, two [29%] of seven goblet cell-deficient and eight [57%] of 14 crypt cell dysplastic lesions [p = 0.726]. Follow-up biopsies or resections were available for 92 low-grade lesions from 71 patients; 55 [60%] lesions, including 19 [49%] of 39 hypermucinous, 10 [59%] of 17 goblet cell-deficient and 26 [72%] of 36 crypt cell dysplastic lesions [p = 0.116], were associated with subsequent detection of HGD [n = 34; 37%] or adenocarcinoma [n = 21; 23%] at the site of previous biopsy or in the same colonic segment within a mean follow-up time of 12 months [range: <1-73].

CONCLUSIONS

Hypermucinous, goblet cell-deficient and crypt cell dysplasias have distinct clinicopathological features but appear to have a similar high risk of association with advanced neoplasia [HGD or adenocarcinoma]. More than half of the lesions [66%] presented as flat/invisible dysplasia, suggesting that IBD patients may benefit from random biopsy sampling in addition to targeted biopsies. Although not uncommonly associated with conventional dysplasia, non-conventional dysplasia may be the only dysplastic subtype identified in IBD patients. Therefore, it is important to recognize these non-conventional subtypes and recommend complete removal and/or careful examination and follow-up.

The Significance of Flat/Invisible Dysplasia and Nonconventional Dysplastic Subtypes in Inflammatory Bowel Disease: A Review of Their Morphologic, Clinicopathologic, and Molecular Characteristics

Patients with inflammatory bowel disease are at significantly increased risk of dysplasia and colorectal cancer (CRC). The early detection, histologic grading, and removal of dysplasia plays a critical role in preventing the development of CRC. With advances in endoscopic visualization and resection techniques, colectomy is no longer recommended to manage dysplasia, unless surveillance colonoscopy detects flat/invisible dysplasia (either high-grade dysplasia or multifocal low-grade dysplasia) or an endoscopically unresectable lesion. Although there are numerous review articles and book chapters on the morphologic criteria of conventional (intestinal type) dysplasia, the most well-recognized form of dysplasia, at least 7 distinct nonconventional morphologic patterns of epithelial dysplasia have been recently described in inflammatory bowel disease. Most practicing pathologists are not familiar with these nonconventional subtypes and thus, may even overlook some of these dysplastic lesions as benign or reactive. However, the recognition of these subtypes is important, as some of them appear to have a high risk of developing advanced neoplasia (high-grade dysplasia or CRC) and often show molecular alterations characteristic of advanced neoplasia. This review briefly describes the morphologic criteria of conventional dysplasia but predominantly focuses on all 7 nonconventional subtypes as well as our understanding of their clinicopathologic and molecular features that can assist in their risk stratification.

Gastric Intestinal Metaplasia in Mucosa Adjacent to Gastric Cancers Is Rarely Associated With the Aneuploidy That Is Characteristic of Gastric Dysplasia or Cancer

Most gastric cancers (GCs) are thought to develop via gastric intestinal metaplasia (GIM)-dysplasia-carcinoma pathway. Patients with extensive and/or incomplete GIM have been reported to have a higher risk of GC. GIM can also display dysplasia-like cytoarchitectural atypia limited to the bases of gastric pits without surface involvement. However, only a small proportion of GIM patients will develop gastric neoplasia, and it remains questionable if GIM is a direct precursor. A cohort of 82 GC patients with GIM who underwent gastrectomy were analyzed. DNA flow cytometry was performed on 109 GIM samples (including 88 predominantly complete GIM and 21 predominantly incomplete GIM subclassified based on morphology) obtained from adjacent mucosa of the 82 GCs. Only 2 (2%) of the 109 GIM samples demonstrated aneuploidy, both from 2 minority patients (Asian and Hispanic) with limited and complete GIM and no cytoarchitectural atypia. The remaining 107 GIM samples showed mild to focally moderate basal gland (metaplastic) atypia limited to the bases of gastric pits, but they all demonstrated normal DNA content regardless of anatomic location, histologic GIM subtype, or varying degrees of basal gland atypia. In conclusion, the vast majority of the GIM samples (98%) lack the aneuploidy that is characteristic of gastric dysplasia or cancer. This indicates that aneuploidy usually occurs after the development of gastric dysplasia rather than at the stage of GIM. The finding also suggests that the presence of GIM alone may not be sufficient to suggest an increased risk for GC and that the inclusion of other high-risk features (ie, extensive GIM, dysplasia, racial minorities, and/or family history of GC in a first-degree relative) and/or aneuploidy ought to play a role in the selection of GIM patients who may warrant endoscopic surveillance. Finally, GIM with mild to focally moderate basal gland atypia is likely to represent metaplastic atypia in most cases.

Non-conventional dysplastic subtypes in inflammatory bowel disease: a review of their diagnostic characteristics and potential clinical implications

The early detection and grading of dysplasia is the current standard of care to minimize mortality from colorectal cancer (CRC) in patients with inflammatory bowel disease. With the development of advanced endoscopic resection techniques, colectomy is now reserved for patients with invisible/flat dysplasia (either high-grade [HGD] or multifocal low-grade dysplasia) or endoscopically unresectable lesions. Although most pathologists are familiar with the morphologic criteria of conventional (intestinal type) dysplasia, the most well-recognized form of dysplasia, an increasing number of diagnostic material has led to the recognition of several different morphologic patterns of epithelial dysplasia. The term “non-conventional” dysplasia has been coined to describe these changes, but to date, the recognition and full appreciation of these novel forms of dysplasia by practicing pathologists is uneven. The recognition of these non-conventional subtypes is becoming increasingly important, as some of them appear to have a higher risk of developing HGD or CRC than conventional dysplasia or sporadic adenomas. This review describes the morphologic characteristics of all seven non-conventional subtypes that have been reported to date as well as our current understanding of their clinicopathologic and molecular features that distinguish them from conventional dysplasia or sporadic adenomas.

Non-conventional dysplasias of the tubular gut: a review and illustration of their histomorphological spectrum

The increasing use of gastrointestinal endoscopic procedures has led to the recognition by histopathologists of non-conventional (or special-type) dysplasias of the gastrointestinal tract. These lesions can be recognised in association with prevalent underlying gastrointestinal conditions, such as Barrett oesophagus, chronic atrophic gastritis, and inflammatory bowel disease. The diagnosis of these special types can be challenging, and their biological behaviours are not fully characterised. The aim of this review is to provide a global view of non-conventional dysplastic lesions observed in the various segments of the tubular gastrointestinal tract and describe their salient features. Furthermore, as the clinical implications of these various subtypes have not been broadly tested in practice and are not represented in most management guidelines, we offer guidance on the best management practices for these lesions.

Non-conventional dysplasia in inflammatory bowel disease is more frequently associated with advanced neoplasia and aneuploidy than conventional dysplasia

AIMS

Several different non-conventional morphological patterns of epithelial dysplasia have been recently described in inflammatory bowel disease (IBD), but there is limited information regarding their clinicopathological and molecular features, as well as potential risk for high-grade dysplasia (HGD) or colorectal cancer (CRC) compared with conventional dysplasia developing in IBD.

METHODS AND RESULTS

A total of 317 dysplastic lesions from 168 IBD patients were analysed. All lesions were re-reviewed and subtyped as either conventional [including tubular adenoma-like (n = 183) and tubulovillous/villous adenoma-like (n = 56)] or non-conventional dysplasia [including dysplasia with increased Paneth cell differentiation (DPD, n = 40), crypt cell dysplasia (CCD, n = 14), goblet cell deficient (GCD, n = 10), hypermucinous (n = 7), sessile serrated lesion (SSL)-like (n = 4) and traditional serrated adenoma (TSA)-like (n = 3)]. DNA flow cytometry was performed on 70 low-grade conventional (n = 24) and non-conventional (n = 46) dysplastic biopsies to determine their malignant potential and molecular pathways to HGD or CRC. Eleven sporadic tubular adenomas with low-grade dysplasia (LGD) were utilised as controls. Seventy-eight non-conventional dysplastic lesions were identified in 56 (33%) of the 168 patients, whereas 239 conventional dysplastic lesions were identified in 149 (89%) patients. Although both non-conventional and conventional dysplasias were most often graded as LGD at diagnosis (83% and 84%, respectively), non-conventional dysplasia (38%) was more likely to develop HGD or CRC in the same colonic segment than conventional dysplasia (19%) on follow-up (P < 0.001). Almost half (46%) of non-conventional dysplastic samples showed aneuploidy, whereas only 8% of conventional dysplasia (P = 0.002) and 9% of sporadic tubular adenomas (P = 0.037) did. Also, non-conventional dysplasia more frequently presented as a flat/invisible lesion (41%) compared with conventional dysplasia (18%) (P < 0.001). Among the non-conventional subtypes (n = 78), DPD was the most common (n = 40; 51%), followed by CCD (n = 14; 18%), GCD (n = 10; 13%), hypermucinous (n = 7; 9%), SSL-like (n = 4; 5%) and TSA-like (n = 3; 4%) variants. Hypermucinous dysplasia (mean = 2.1 cm) was significantly larger than DPD, SSL-like, TSA-like and GCD variants (mean = 1.0, 1.2, 1.2 and 1.9 cm, respectively) (P = 0.037). HGD or CRC was more likely to be associated with CCD (n = 13; 93%), hypermucinous (n = 4; 57%), GCD (n = 4; 40%) and SSL-like (n = 3; 75%) variants than DPD (n = 6; 15%) and TSA-like dysplasia (n = 0; 0%) on follow-up (P < 0.001). Furthermore, the rate of aneuploidy was significantly higher in CCD (100%), hypermucinous (80%) and GCD (25%) variants than in DPD (12%), SSL-like dysplasia (0%) and TSA-like dysplasia (0%) (P < 0.001).

CONCLUSIONS

Non-conventional morphological patterns of dysplasia are not uncommon in IBD, detected in 33% of the patients. The higher frequencies of advanced neoplasia (HGD or CRC) and aneuploidy in non-conventional dysplasia, in particular CCD, hypermucinous and GCD variants, suggest that they may have a higher malignant potential than conventional dysplasia or sporadic tubular adenomas, and thus need complete removal and/or careful follow-up. Greater than 40% of non-conventional dysplasia presented as a flat/invisible lesion, suggesting that IBD patients may benefit from random biopsy sampling in addition to targeted biopsies. The majority of non-conventional subtypes appear to develop via the chromosomal instability pathway, whereas an alternative serrated pathway may be responsible for the development of at least a subset of SSL-like and TSA-like dysplasias.

DNA aneuploidy with image cytometry for detecting dysplasia and carcinoma in oral potentially malignant disorders: A prospective diagnostic study

BACKGROUND

Current evidence on diagnostic value of aneuploidy with DNA image cytometry (ICM) using brushings for oral potentially malignant disorders (OPMD) is limited by sample size and inconsistent classification criteria of aneuploidy. This study aimed to explore the optimal cut-off values of DNA content and evaluate the diagnostic accuracy of DNA-ICM for detecting dysplasia and/or carcinoma in OPMD.

MATERIALS AND METHODS

A total of 401 consecutive patients with OPMD were enrolled in this prospective diagnostic study. Brushing and biopsy sample form each patient was processed by DNA-ICM and histological examination respectively.

RESULTS

When the optimal cut-off of at least one aneuploid cell with DNA index (DI) ≥2.3, the area under the curves (AUC) was 0.735 and positive predictive value was 92.7% for detecting dysplasia within OPMD. When the optimal cut-off of at least one aneuploid cell with DI ≥ 3.5, the AUC was 0.851 and negative predictive values was 96.8% for detecting carcinoma within OPMD. Importantly, multivariate analysis revealed that aneuploidy with DI ≥ 2.3 in OPMD was significantly associated with dysplasia risk (adjusted OR, 5.52; 95%CI, 2.90-10.51; P < .001), and aneuploidy with DI ≥ 3.5 in OPMD was strongly associated with malignant risk (adjusted OR, 21.05; 95%CI, 9.34-47.41; P < .001).

CONCLUSIONS

This largest-scale diagnostic study optimized the criteria of aneuploidy cytology for noninvasive detection of oral dysplasia and carcinoma within OPMD. DNA aneuploidy in OPMD was an independent marker that strongly associated with oral dysplasia/carcinoma. Our findings suggest that DNA-ICM may serve as a useful noninvasive adjunctive tool for oral cancer and OPMD screening.

Nonconventional dysplasia in patients with inflammatory bowel disease and colorectal carcinoma: a multicenter clinicopathologic study

Several types of nonconventional dysplasia have been recently described in inflammatory bowel disease (IBD). However, strict morphologic criteria are lacking, and their clinicopathologic features (including potential association with conventional dysplasia and/or colorectal cancer [CRC]) are poorly understood. A total of 106 dysplastic or serrated lesions in 58 IBD patients with CRC were retrospectively identified from five institutions. Thirty-six cases of nonconventional dysplasia were identified in 26 (45%) of the 58 patients and occurred with similar frequency in men and women (58% and 42%, respectively), with a mean age of 54 years (range: 24-73) and a long history of IBD (mean: 17 years, range: 2-43). Six morphologic patterns were recognized. Hypermucinous dysplasia (n = 15; 42%) presented as either a 'pure type' (n = 5; 14%) or a 'mixed type' with either conventional or another nonconventional subtype (n = 10; 28%). Serrated lesions, as a group, were equally common (n = 15; 42%) and included three variants: traditional serrated adenoma-like (n = 10; 28%), sessile serrated lesion-like (n = 1; 3%), and serrated lesion, not otherwise specified (n = 4; 11%). Dysplastic lesions with increased Paneth cell differentiation (n = 4; 11%) and goblet cell deficient dysplasia (n = 2; 6%) were rare. Twelve (46%) of the 26 patients had only nonconventional dysplasia, whereas the remaining 14 patients (54%) had both nonconventional and conventional dysplasias. Nonconventional dysplasia was most often graded as low-grade dysplasia (81%), which was less common in conventional dysplasia (37%) (p = 0.003). When present alone, nonconventional dysplasia was predominantly found in the left colon (81%, p = 0.006) as a polypoid or raised lesion (75%, p < 0.001) compared with when it occurred simultaneously with conventional dysplasia (35% and 50%, respectively). When both nonconventional and conventional dysplasias occurred simultaneously, they were found in the same colonic segment in all but 3 patients (79%). Nonconventional dysplasia was also commonly detected in the same colonic segment as CRC or immediately adjacent to the CRC at a rate (85%) similar to conventional dysplasia (96%). CRC occurring in patients with only nonconventional dysplasia was more likely to be high-grade (poorly differentiated; 36%) than CRC that occurred in association with conventional dysplasia (10%) (p = 0.026). In conclusion, nonconventional dysplasia is common in IBD patients with CRC. It appears to develop in the same field of carcinomatous development, and it is not uncommonly associated with conventional dysplasia.

DNA flow cytometric analysis of paraffin-embedded tissue for the diagnosis of malignancy in bile duct biopsies

Differentiation of reactive versus neoplastic epithelial changes can be challenging in bile duct biopsies. The samples are often scant, distorted, and mixed with significant inflammation, ulceration, and/or debris. Histological confirmation of malignancy is often required before the initiation of surgical therapy, and an erroneous diagnosis of malignancy can lead to unnecessary clinical management. Aneuploidy assessment by DNA flow cytometry was performed on formalin-fixed paraffin-embedded (FFPE) tissue from 63 bile duct biopsies: 10 with a malignant diagnosis (7 with adenocarcinoma and 3 with at least high-grade dysplasia [HGD]); 3 with an atypical diagnosis showing rare atypical glands/cells, concerning but not definite for malignancy; 28 likely reactive biopsies with acute/chronic inflammation, ulceration, and/or mild nuclear atypia; and 22 additional benign biopsies without significant inflammation, ulceration, or nuclear atypia. Aneuploidy was detected in 7 (70%) of the 10 biopsies with definite neoplasia (5 of 7 adenocarcinoma cases and 2 of 3 at least HGD cases), all 3 (100%) atypical biopsies, and none of the 50 benign biopsies. All 3 atypical cases with aneuploidy were subsequently found to have adenocarcinoma (n = 2) or HGD (n = 1). Among the 2 cases of at least HGD with aneuploidy, 1 case developed adenocarcinoma, but no follow-up information was available in the other case. The remaining 1 case of at least HGD, despite having normal DNA content, was found to have adenocarcinoma on follow-up. None of the 50 benign cases (further supported by normal DNA content) developed adenocarcinoma within a mean follow-up time of 37 months (range: 0-282 months). The estimated sensitivity of aneuploidy as a diagnostic marker of malignancy (adenocarcinoma and HGD) was 70%, with the specificity of 100%, positive predictive value of 100%, and negative predictive value of 94%. In conclusion, DNA flow cytometry using FFPE tissue from bile duct biopsies demonstrates a high rate of aneuploidy (70%) in malignant cases and normal DNA content in all benign biopsies. Although the sample size is small, the results indicate that this assay can be potentially useful in challenging atypical cases, where morphological evaluation is limited by scarcity of atypical glands/cells, inflammation, and/or ulceration.

Newly recognized non-adenomatous lesions associated with enteric carcinomas in inflammatory bowel disease - Report of six rare and unique cases

It is the current view that the inflammatory bowel disease (IBD)-associated precancerous lesions may be adenomatous (with classic cytologic dysplasia) and non-adenomatous (without frank cytologic dysplasia), and the latter ones are in various histomorphologies including serrated, mucinous, eosinophilic (goblet cell deficient), and differentiated (dysplasia with terminal epithelial differentiation) types. By retrospectively reviewing the surgically resected IBD-associated colorectal and ileal carcinomas (×53), analyzing the background epithelial changes/lesions in the mucosa surrounding and adjacent to invasive carcinomas, and testing the key molecular profile (KRAS, BRAF, PIK3CA, NRAS, p53, mismatch repair proteins, and SAT-B2) known to be involved in colorectal carcinogenesis, we identified 6 representative, rare and unique cases, in which non-adenomatous lesions were clearly in vicinity and in transition to invasive carcinomas. Furthermore, we identified certain colonic carcinoma-related molecular alterations, and thus further confirmed the neoplastic nature of various non-adenomatous lesions. It was also revealed that non-adenomatous lesions are heterogeneous in both morphology and molecular alterations, and that it is common to have more than one type of lesions be associated with a carcinoma. Moreover, mixed focal adenomatous dysplasia was common, which may be the necessary step in the malignant transformation of the non-adenomatous lesions.