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Programmed cell death-ligand 1 (PD-L1) clone 22C3 is the only Food and Drug Administration-approved companion diagnostic test for pembrolizumab for the treatment of esophageal squamous cell carcinoma (ESCC). However, prior studies conducted in Asia and Europe have used various PD-L1 antibody clones other than 22C3. We aimed to study the expression profile of PD-L1, specifically of clone 22C3, in ESCC and its significance with regards to histological features, clinical parameters, and overall survival in a case series from two large US hospital systems. PD-L1 (22C3) immunohistochemistry was performed on 82 specimens obtained from 75 patients. Electronic medical records were reviewed to obtain the clinical and follow-up data. Of these specimens, 39 % (32/82) were negative for PD-L1 (22C3) expression (combined positive score (CPS) of 0). The remaining 50 specimens were positive, with CPSs ranging from 1 to 100. Treated specimens showed decreased PD-L1 (22C3) expression compared to untreated specimens. In the multivariate Cox proportional hazards regression model, PD-L1 (22C3) expression was shown to be a favorable prognostic factor for overall survival (p = 0.03, hazard ratio 0.16) only when the CPSs were ≥ 25, independent of surgery, definitive chemotherapy and/or radiotherapy, immunotherapy, and initial clinical stages. We performed a comprehensive study to investigate the expression profile of PD-L1 clone 22C3 in the US patients with ESCC. Our analysis showed that PD-L1 (22C3) expression decreased in treated specimens, and a CPS of ≥25 was associated with a favorable prognosis., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: Differentiating pancreatic serous cystadenoma (SCA) from well-differentiated neuroendocrine tumors (WDNETs) based on histomorphology is critical yet challenging, particularly in small biopsy samples. Our study aimed to examine the expression profile of INSM1 in cytologic and surgical resection specimens from pancreatic SCA to evaluate its potential as a discriminative marker against pancreatic WDNET., Methods: We characterized INSM1 immunohistochemistry in 34 patients with pancreatic SCA, comprising 23 surgical resections and 11 cytology specimens. As a control, we used 28 cytology specimens from pancreatic WDNET. Clinical information was retrieved through a review of electronic medical records., Results: All 11 pancreatic SCA cytology specimens and 15 of 23 pancreatic SCA surgical resections exhibited absent INSM1 immunostaining. Each of the remaining eight surgical resection specimens demonstrated 1 % immunoreactivity. In contrast, 27 out of 28 (96 %) pancreatic WDNET cytology specimens were positive for INSM1 immunostaining, with a median immunoreactivity of 90 % and a range of 30-90 %. Overall, INSM1 immunostains perform similarly to chromogranin and synaptophysin in pancreatic SCA., Conclusions: The results indicate that INSM1 immunohistochemistry staining may serve as a useful neuroendocrine marker to differentiate pancreatic SCA from pancreatic WDNET in clinical practice. To our knowledge, this represents the first large-scale study to evaluate INSM1 immunostaining in surgical and cytology specimens from pancreatic SCA., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Autoimmune gastritis (AIG) is a clinicopathologic diagnosis requiring characteristic histopathology and correlation with laboratory work-up. To better understand how the diagnosis of AIG is made and reported in the pathology community, we conducted an anonymous web-based survey which was circulated among a diverse group of pathologists. Excluding trainees there were 64 respondents: 25 academic gastrointestinal pathologists (AGI, 39%), 22 academic general pathologists (AGP, 34%), 17 private general pathologists (PP, 27%). Our survey results highlighted variations in work-up and sign-out practices. The type of metaplasia needed to diagnose AIG lacked consensus. There was variation in accurate interpretation of immunostains with a trend towards more accurate diagnosis of enterochromaffin-like (ECL) cell hyperplasia by AGI (92%) and AGP (95%) than PP (71%) (p = 0.07). G-cells in antrum on neuroendocrine immunostain, a mimicker of ECL cell hyperplasia, was more frequently misdiagnosed by PP/ AGP (44%), versus AGI (12%) (p = 0.02). A triple immunostain panel (H. pylori, neuroendocrine, gastrin) was used in the work-up of AIG by 72% of AGI versus 23% AGP and 12% PP (p = 0.000061). The less-specific term "atrophic gastritis" was used in the diagnostic line more by respondents with >10 years sign-out experience compared with others (p = 0.04). In conclusion, the survey results highlighted deficiencies in the interpretation of neuroendocrine immunostains which is crucial for AIG diagnosis, as well as variation in reporting practices and definitions. Uniform criteria and terminology are needed in this field to improve communication with clinicians, resulting in appropriate testing and follow-up., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Aims: CDH1 germline mutation is associated with high penetrance of hereditary diffuse gastric cancer (HDGC). Due to the lack of endoscopically identifiable lesions, routine surveillance is ineffective in the early detection of gastric cancer, and risk-reduction gastrectomy is often recommended. Many academic pathology departments elect to submit the entire gastrectomy specimen for histological examination, which is associated with significantly increased cost, technical and professional time, and turnaround time., Methods: We present our experience with 5 completely submitted and 2 representatively submitted prophylactic total gastrectomy cases in HDGC patients., Results: Multifocal intramucosal signet ring cell carcinoma was identified in all cases except one, in which only in situ carcinoma was identified. The tumoral foci (2 to 35 per case; average 14.4) were concentrated in proximal stomach. No submucosal invasion or nodal metastases was seen in any case. The final stage was either stage 0 (pTisN0cM0) or stage 1a (pT1aN0cM0)., Conclusions: Our findings are in line with that reported in the literature. Considering that deeply invasive carcinoma is very rare in this situation, and no further treatment is indicated for the vast majority of those patients, complete submission and pathologic examination of the entire stomach provides little additional value for routine clinical management. We propose a two-step approach with targeted submission of the proximal stomach, and subsequent entire submission of the remaining stomach if no intramucosal carcinoma is identified during the initial targeted examination., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Current literature shows a variable degree of concordance between endoscopic and histopathologic findings in gastric mucosal biopsies. Most prior studies have focused on specific gastric entities such as gastritis in patients with high prevalence of Helicobacter pylori (H. pylori). In this study, we assess concordance between histologic and endoscopic findings in a wide spectrum of targeted as well as non-targeted gastric endoscopic biopsies., Methods: We retrospectively reviewed pathology database and slides at Hershey Medical Center to identify 630 gastric mucosal biopsies obtained from 525 consecutive patients. The corresponding clinical and endoscopic findings were retrieved from the electronic medical record., Results: The rate of abnormal endoscopic and histologic findings was 72.9% and 74.4%, respectively, with Cohen's ĸ coefficient of 0.24. There were 444 (70.5%) concordant cases and 186 (29.5%) discordant cases (88 cases with abnormal endoscopy but normal histology, and 98 cases with normal endoscopy but abnormal histology). Some endoscopic findings, in particular, mass, polyp, ulcer, and nodule/papule were highly concordant with abnormal histopathologic findings; while other endoscopic findings such as inflammatory changes, normal and prominent folds were associated with normal and a variety of abnormal histopathology. Multivariate analysis showed no significant association between intestinal metaplasia and H. pylori in this study., Conclusions: Histopathologic-endoscopic correlation in gastric biopsies varies depending on endoscopic mucosal patterns. Intestinal metaplasia may not have a significant association with H. pylori infection in populations with low prevalence of H. pylori., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The clinical decision to excise intraductal papilloma (IDP) without atypia diagnosed on biopsy remains controversial. We sought to establish clinical and histologic predictors (if any) which may predict upgrade in IDP. 296 biopsies (in 278 women) with histologic diagnosis of IDP without atypia were retrospectively identified and placed into Incidental (no corresponding imaging correlate), or Non-incidental (positive imaging correlate) groups. 253/296 (85.5%) cases were non-incidental, and 43/296 (14.5%) were incidental. 73.1% (185/253) non-incidental and 48.8% (21/43) incidental cases underwent excision. 12.4% (23/185) non-incidental cases underwent an upgrade to cancer or high-risk lesion; namely 8-Ductal carcinoma in situ (DCIS), 8-atypical ductal hyperplasia (ADH), 6-lobular neoplasia, and 1-flat epithelial atypia. There was no histopathologic feature on the biopsy in the non-incidental group which predicted upgrade; however a past history of atypia was significantly associated with upgrade. 2 of the 21 incidental cases upgraded (1 to ADH and 1 to lobular neoplasia); the former had a past history of ADH. Both incidental upgrades were >1 mm in size, and were not completely excised on the biopsy. None of the incidental cases which appeared completely excised on biopsy upgraded, irrespective of the size on biopsy. These findings suggest that all non-incidental IDPs should be considered candidates for surgical excision, given the 12.4% upgrade rate and no definitive histologic predictors of upgrade. Patients with incidental IDPs (if <1 mm, completely excised on biopsy and with no history of high risk breast lesion) can be spared excision., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Academic and community hospital pathology groups are increasingly adopting subspecialized service models for surgical pathology (SP) practice. Reasons cited include improvements in sign-out efficiency, quality and accuracy, enhancement of clinician-pathologist communications, and augmentation of resident training quality. However, there is a paucity of published quantitative data regarding the outcomes of transitioning from general to subspecialized SP service coverage. Retrospective assessment of the frequencies and outcomes of SP extramural consultations requested by faculty at our institution was performed, encompassing 2 consecutive years each of subspecialized and general SP service models. The frequencies of extramural consultations between the 2 practice models were not significantly different (0.25% vs 0.21%, P = .142). Although more pathology cases were sent out in gastrointestinal (0.29% vs 0.14%, P = .007), gynecologic (0.16% vs 0.02%, P = .009), and pulmonary (1.73% vs 0.28%, P = .008) services during the "subspecialization" era, fewer pediatric cases were sent out (0.48% vs 1.69%, P = .008). Importantly, the transition to the subspecialized model was associated with a marked reduction in the frequency of major disagreements between the original diagnosis and the consultant's diagnosis (1.8% vs 9.3%, P = .018). Our study supports the value of the subspecialized SP sign-out model for increasing diagnostic accuracy and enhancing the quality of patient care., (Copyright © 2016 Elsevier Inc. All rights reserved.)