Interobserver agreement and the impact of mentorship on the diagnosis of inflammatory bowel disease-associated dysplasia among subspecialist gastrointestinal pathologists

SATB2 Loss Is a Sensitive Biomarker for Dysplasia in Inflammatory Bowel Disease

Loss of SATB2 expression has emerged as a promising biomarker for dysplasia in inflammatory bowel disease (IBD), but its sensitivity and specificity remain unclear. We retrospectively evaluated immunohistochemical (IHC) staining of SATB2 and p53 in colorectal biopsies from 37 IBD patients (25 men and 12 women; median age: 48 years) with suspected dysplasia. The cohort included 26 ulcerative colitis (70%) and 11 Crohn's disease (30%). Fourteen patients (38%) developed IBD-associated invasive carcinoma, and 18 (49%) had persistent dysplasia on follow-up. Histologic review identified 80 lesions initially diagnosed as negative (16%), indefinite (39%), low-grade (36%), and high-grade (9%) dysplasia. IHC revealed aberrant p53 in 35 lesions (44%) and SATB2 loss in 42 lesions (53%), with 19 (24%) showing both abnormalities. Reappraisal of diagnoses combining histology and IHC reclassified lesions into indefinite (20%), low-grade (63%), and high-grade (17%) dysplasia. Lesions with SATB2 loss alone were more frequently of lower grade (P = .003). Dysplasia types included 15 conventional dysplasia (19%) and 65 nonconventional dysplasia (81%). The rates of p53 abnormality, SATB2 loss, and their combination were similar in nonconventional dysplasia (45%, 55%, and 75%, respectively) and conventional dysplasia (40%, 47%, and 67%, respectively) and comparable between cancer patients (50%, 56%, and 74%, respectively) and noncancer patients (39%, 50%, and 72%, respectively). Missed dysplasias in cancer patients were all nonconventional, and lesions with p53 abnormality more likely progressed to cancer (P = .002). In conclusion, SATB2 loss is a sensitive marker for IBD-associated dysplasia. Combined use of SATB2 and p53 IHC improves dysplasia detection and reduces false-negative diagnosis, supporting its application into routine diagnostic practice.

Nonconventional dysplasia in patients with inflammatory bowel disease and colorectal adenocarcinoma: a case-cohort study

BACKGROUND AND AIMS

Patients with inflammatory bowel disease (IBD) face increased risk of colorectal cancer (CRC). While the natural history of conventional dysplastic precursor lesions has been well-studied, the neoplastic potential of recently described nonconventional (NC) IBD-associated colonic mucosal lesions is unclear. We aimed to assess the incidence of antecedent NC lesions in patients with IBD who developed CRC.

METHODS

A case-cohort study was performed to include patients with a diagnosis of IBD with or without CRC who underwent at least 2 surveillance endoscopic procedures at our institution between 1/1/2007 and 5/31/2023. NC lesions included serrated change and indefinite for dysplasia. Detection rates pre- and post-introduction of high-definition (HD) surveillance colonoscopy were compared.

RESULTS

In total, 87 patients with IBD and CRC and 200 patients with IBD without CRC were identified. Of the cases, a majority had ulcerative colitis (n = 52, 60%), most commonly with extensive involvement (n = 46, 89%). Conventional (hazard ratio [HR] 2.18, 95% confidence interval [CI] 1.34-3.52) and NC (HR 2.28, 95% CI 1.59-3.26) lesions were associated with increased risk of CRC. Conventional lesions in the post-HD era appeared to have a stronger association with CRC (HR 2.79, 95% CI 1.62-4.77) than NC lesions (HR 1.62, 95% CI 0.86-3.06).

CONCLUSIONS

Both conventional and NC lesions seem to be associated with increased risk of CRC. Conventional lesions are more strongly associated with CRC than NC lesions in the post-HD era, but misclassifications in the pre-HD era may have resulted in a biased increased risk estimate for NC lesions.

p53 mutation biases squamocolumnar junction progenitor cells towards dysplasia rather than metaplasia in Barrett's oesophagus

BACKGROUND

While p53 mutations occur early in Barrett's oesophagus (BE) progression to oesophageal adenocarcinoma (EAC), their role in gastric cardia stem cells remains unclear.

OBJECTIVE

This study investigates the impact of p53 mutation on the fate and function of cardia progenitor cells in BE to EAC progression, particularly under the duress of chronic injury.

DESIGN

We used a BE mouse model (L2-IL1β) harbouring a Trp53 mutation (R172H) to study the effects of p53 on Cck2r+ cardia progenitor cells. We employed lineage tracing, pathological analysis, organoid cultures, single-cell RNA sequencing (scRNA-seq) and computational analyses to investigate changes in progenitor cell behaviour, differentiation patterns and tumour progression. Additionally, we performed orthotopic transplantation of sorted metaplastic and mutant progenitor cells to assess their tumourigenic potential in vivo.

RESULTS

The p53 mutation acts as a switch to expand progenitor cells and inhibit their differentiation towards metaplasia, but only amidst chronic injury. In L2-IL1β mice, p53 mutation increased progenitors expansion and lineage-tracing with a shift from metaplasia to dysplasia. scRNA-seq revealed dysplastic cells arise directly from mutant progenitors rather than progressing through metaplasia. In vitro, p53 mutation enhanced BE progenitors' organoid-forming efficiency, growth, DNA damage resistance and progression to aneuploidy. Sorted metaplastic cells grew poorly with no progression to dysplasia, while mutant progenitors gave rise to dysplasia in orthotopic transplantation. Computational analyses indicated that p53 mutation inhibited stem cell differentiation through Notch activation.

CONCLUSIONS

p53 mutation contributes to BE progression by increasing expansion and fitness of undifferentiated cardia progenitors and preventing their differentiation towards metaplasia.

Clinicopathologic and Molecular Characterization of Inflammatory Bowel Disease-Associated Neuroendocrine Carcinomas and Mixed Neuroendocrine-Non-Neuroendocrine Neoplasms

The pathogenesis of neuroendocrine carcinomas (NECs) and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) in the gastrointestinal tract remains poorly understood. This study aims to characterize the clinicopathologic and molecular features of NEC/MiNEN in patients with inflammatory bowel disease (IBD). Eighteen surgically resected IBD-associated intestinal carcinomas with a minimum of 30% neuroendocrine component were collected from 6 academic centers and compared with a control group of 12 IBD-associated carcinomas lacking neuroendocrine differentiation. Both groups exhibited a male predominance and similar age distribution. The NEC/MiNEN group was more likely to have a higher percentage of Crohn disease (9/18 vs 1/12; P = .024), occur in the rectum (9/18 vs 3/12) and small intestine (4/18 vs 0/12) (P < .01), be diagnosed on resection without a preceding biopsy (6/18 vs 0/12; P = .057), and have unidentifiable precursor lesions (10/18 vs 1/12; P = .018) than the control group. Synchronous carcinoma, advanced tumor stage (pT3 and pT4), and lymph node metastasis occurred at similar rates; however, the NEC/MiNEN group had a higher incidence of angiovascular invasion (14/18 vs 4/12; P = .024), distant metastasis (8/18 vs 1/12; P = .049), mortality (8/18 vs 2/12; P = .058), and worse survival (Kaplan-Meier; P = .023) than the control group. All tested cases were mismatch repair proficient. A Ki-67 proliferation index ranged from 25% to 100%. Next-generation sequencing in 11 NEC/MiNEN cases revealed low tumor mutational burdens but complex genetic abnormalities commonly involving TP53 (9/11; 82%), FBXW7 (4/11; 36%), and APC (3/11; 27%) genes, with the other genetic alterations randomly occurring in 1 or 2 cases. The neuroendocrine component, which shared similar molecular alterations as the nonneuroendocrine component, was subcategorized into intermediate (G3a) and high grade (G3b); the higher grade correlated with more genetic alterations. In conclusion, IBD-associated NEC/MiNEN shows diverse histologic features, variable precursor lesions, intricate genetic abnormalities, and aggressive biologic behavior. The classification and grading of gastrointestinal NEC/MiNEN may be refined for better clinical 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.

Erythrophagocytosis is not a reproducible finding in liver biopsies, and is not associated with clinical diagnosis of hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease with high mortality. Liver involvement is common (based on elevated liver function tests) with most patients demonstrating acute hepatitis. Liver biopsies are frequently obtained in the setting of suspected HLH for the purpose of identification of erythrophagocytosis, and if present, this finding is thought to suggest or support the diagnosis of HLH. However, there are problems with this approach; in particular, we do not know whether this finding is reproducible or whether it is specific to HLH. Therefore, we conducted a multi-institutional study in which experienced liver pathologists reviewed images taken from liver biopsies from patients with normal liver, acute hepatitis, possible HLH, and clinical HLH to determine if there was agreement about the presence or absence of erythrophagocytosis, and to ascertain whether the finding corresponds to a clinical diagnosis of HLH. Twelve liver pathologists reviewed 141 images in isolation (i.e., no clinical information or diagnosis provided). These came from 32 patients (five normal, 17 acute hepatitis, six HLH, four possible HLH). The pathologists classified each image as negative, equivocal, or positive for erythrophagocytosis. Kappa was .08 (no agreement) for case-level and 0.1 for image-level (1.4% agreement, based on two images which were universally considered negative). There was no difference in the proportion of pathologists who diagnosed erythrophagocytosis among those with different diagnoses at case or image-level (p = 0.82 and p = 0.82, respectively). Thus, erythrophagocytosis is an entirely unreliable histologic parameter in liver, as it is irreproducible and not demonstrably associated with a clinical disease (namely, HLH). Unless and until more reliable guidelines can be established, pathologists should refrain from commenting on the presence or absence of erythrophagocytosis in liver biopsy.

Automated Nuclear Segmentation in Head and Neck Squamous Cell Carcinoma Pathology Reveals Relationships between Cytometric Features and ESTIMATE Stromal and Immune Scores

The tumor microenvironment (TME) plays an important role in the progression of head and neck squamous cell carcinoma (HNSCC). Currently, pathologic assessment of TME is nonstandardized and subject to observer bias. Genome-wide transcriptomic approaches to understanding the TME, while less subject to bias, are expensive and not currently a part of the standard of care for HNSCC. To identify pathology-based biomarkers that correlate with genomic and transcriptomic signatures of TME in HNSCC, cytometric feature maps were generated in a publicly available data set from a cohort of patients with HNSCC, including whole-slide tissue images and genomic and transcriptomic phenotyping (N = 49). Cytometric feature maps were generated based on whole-slide nuclear detection, using a deep-learning algorithm trained for StarDist nuclear segmentation. Cytometric features in each patient were compared to transcriptomic measurements, including Estimation of Stromal and Immune Cells in Malignant Tumor Tissues Using Expression Data (ESTIMATE) scores and stemness scores. With correction for multiple comparisons, one feature (nuclear circularity) demonstrated a significant linear correlation with ESTIMATE stromal score. Two features (nuclear maximum and minimum diameter) correlated significantly with ESTIMATE immune score. Three features (nuclear solidity, nuclear minimum diameter, and nuclear circularity) correlated significantly with transcriptomic stemness score. This study provides preliminary evidence that observer-independent, automated tissue-slide analysis can provide insights into the HNSCC TME which correlate with genomic and transcriptomic assessments.

Management of pouch neoplasia: consensus guidelines from the International Ileal Pouch Consortium

Surveillance pouchoscopy is recommended for patients with restorative proctocolectomy with ileal pouch-anal anastomosis in ulcerative colitis or familial adenomatous polyposis, with the surveillance interval depending on the risk of neoplasia. Neoplasia in patients with ileal pouches mainly have a glandular source and less often are of squamous cell origin. Various grades of neoplasia can occur in the prepouch ileum, pouch body, rectal cuff, anal transition zone, anus, or perianal skin. The main treatment modalities are endoscopic polypectomy, endoscopic ablation, endoscopic mucosal resection, endoscopic submucosal dissection, surgical local excision, surgical circumferential resection and re-anastomosis, and pouch excision. The choice of the treatment modality is determined by the grade, location, size, and features of neoplastic lesions, along with patients' risk of neoplasia and comorbidities, and local endoscopic and surgical expertise.