Enteropathy-associated T cell lymphoma is a rare lymphoma specific to the gastrointestinal system, arising from intraepithelial T lymphocytes, that is often associated with celiac disease. We report a 53-year-old female patient with no previous disease who presented with severe abdominal pain. Physical examination revealed diffuse abdominal tenderness and abdominal guarding and the patient underwent emergency surgery with a diagnosis of acute abdomen. During the operation, a 20-cm mass was found located on Treitz ligament, invading the duodenum and pancreatic head and perforating the jejunum. Histologically, medium-sized monomorphic atypical lymphocyte infiltration with dark nucleus and narrow cytoplasm was seen in the layers of mucosa, submucosa, muscular wall, and serosa of the duodenum. The final pathological diagnosis was "enteropathy-associated T cell lymphoma type 2" based on immunohistochemical and serological findings. Based on the World Health Organization 2008 criteria, enteropathy-associated T cell lymphoma has two subtypes. Type 1 enteropathy-associated T cell lymphoma is associated with celiac disease and has HLA DQ2 and HLA DQ8 genotype. Enteropathy-associated T cell lymphoma 2 enteropathy-associated T cell lymphoma seldom occurs and is not associated with celiac disease.

Background and Objective: Bladder cancer (BC) is the ninth most common malignancy worldwide. Squamous cell carcinoma (SqCC), a rare histological variant, accounts for approximately 2–5% of all BC cases. Compared to urothelial carcinoma, the predominant subtype, research on SqCC remains limited and shows inconsistent findings regarding prognosis. This study aimed to compare survival outcomes between patients with SqCC and those with pure urothelial carcinoma (PUC). Methods: This retrospective, observational study analyzed pathology reports from 2549 transurethral resections of bladder tumors and 632 cystectomies performed at our institution between 1 December 2010 and 31 December 2023. Following pathological re-evaluation, 33 patients with SqCC and 132 with PUC were identified. After 1:3 propensity score matching, 20 patients with SqCC and 58 with PUC were included in the final analysis. Demographic, clinicopathological features, and survival outcomes were compared between groups. Results: The median follow-up was 2.31 years (range: 0.17–13.50). No significant differences in baseline demographic or clinical characteristics were observed, except for the type of surgery. Kaplan–Meier analysis demonstrated no significant differences in disease-free survival (DFS; p = 0.961) or overall survival (OS; p = 0.847) between SqCC and PUC groups. Multivariate Cox regression analysis identified T stage, nodal involvement, and adjuvant chemotherapy (CT) as independent predictors of DFS, while sex and metastasis at diagnosis were significant predictors of OS. Conclusion: Survival outcomes (DFS and OS) did not significantly differ between patients with SqCC and patients with PUC. Prognosis was more closely associated with disease stage at diagnosis, sex, and adjuvant CT. Further large-scale studies are warranted.

Synovial sarcoma is a rare malignant mesenchymal neoplasm that typically occurs in soft tissue sites, and the kidney is an uncommon primary location. Previous studies of primary renal synovial sarcoma are limited by small sample sizes, and our understanding remains incomplete. Here, we present the largest multi-institutional case series to date of primary renal synovial sarcoma, with a focus on novel and molecular findings. A total of 70 cases were contributed by multiple institutions. Comprehensive clinical and histopathologic data were collected and analyzed. The mean patient age was 40 years, with a male-to-female ratio of 1.9:1. The most common presenting signs and symptoms were pain and hematuria. The mean tumor size was 11.6 cm (range: 2.3 to 26 cm), with frequent cystic change and necrosis. The mean follow-up was 29 months (range: 2 to 129 mo), and the rates of metastasis, recurrence, and death due to disease were 62.7%, 33.3%, and 50.0%, respectively. Histologically, 56.1% were monophasic synovial sarcoma, 15.1% were biphasic, and 28.8% were poorly differentiated or showed round cell features. Molecularly, SS18::SSX2 fusion was detected in the majority of cases assessed (n=19), followed by SS18::SSX1 fusion (n=6) and a rare SS18::NEDD4 fusion (n=1). Given the morphologic and immunohistochemical overlaps with many other neoplasms, accurate diagnosis with preferably molecular techniques is crucial for appropriate prognostication and treatment of this aggressive tumor.

Background and Objectives: One of the most critical areas of measurement and evaluation in healthcare is pathological evaluation, especially intraoperative consultation. Studies conducted to identify sources of error in this field are usually one-sided; however, in evaluation processes with multiple sources of error, such as intraoperative consultation, generalizability theory can evaluate these sources of error simultaneously in a single analysis, thereby contributing to the field. In this study, the reliability of intraoperative and permanent histopathological evaluations of glial tumors was analyzed using generalizability theory to identify the sources of error in the observed evaluation inconsistencies. Materials and Methods: The study included 319 glial tumor cases that underwent intraoperative evaluation and were analyzed using generalizability theory. Three pathologists performed independent evaluations in two stages. Results: The reliability coefficient calculated for all cases was 0.9234 without radiological information and 0.9243 after learning the radiological information. The reliability coefficient was 0.8875 and 0.8989, respectively, in cases over 18 years of age, and 0.8845 and 0.9062 in cases under 18 years of age. These findings indicate that the addition of radiological information to the evaluation resulted in a slight increase in reliability, particularly in cases under 18 years of age. In all of our reliability assessments for different conditions, the highest variability was found to originate from the rater. Conclusions: The findings suggest that intraoperative evaluation demonstrates a high degree of reliability in the pathological assessment of glial tumors. When differences between the rater and the technique are evaluated together, it is observed that the rater has a more significant impact on reliability. While radiological information is generally considered a factor that increases reliability, it is partially more effective, especially in cases involving individuals under the age of 18, which highlights the importance of multidisciplinary data sharing in intraoperative diagnostic processes.

The differential diagnosis between pleural epithelioid mesothelioma and peripheral lung adenocarcinoma remains a significant diagnostic challenge for pathologists. This study aimed to evaluate the diagnostic efficacy of a multi-antibody immunohistochemical (IHC) panel comprising Napsin A, Caveolin-1, Type III Collagen, and Tenascin-X. While Napsin A and Caveolin-1 are established markers, the diagnostic utility of Tenascin-X and Type III Collagen remains less explored in the current literature. A retrospective IHC analysis was performed on 70 paraffin-embedded tissue blocks, comprising 35 lung adenocarcinomas and 35 epithelioid mesotheliomas, diagnosed between 2005 and 2014. The expression patterns of Napsin A, Caveolin-1, Type III Collagen, and Tenascin-X were evaluated and compared between the two groups. Napsin A showed high sensitivity for adenocarcinoma (94.3%) with minimal expression in mesothelioma (2.9%). Conversely, Caveolin-1 and Tenascin-X emerged as strong markers for mesothelioma, with positivity rates of 97.2% and 88.6%, respectively (p < 0.001). Although Type III Collagen was exclusively expressed in mesothelioma (17.1%) and absent in all adenocarcinoma cases, its low sensitivity limits its standalone utility. Significant statistical differences were observed between the two tumor types for all markers evaluated. Our findings suggest that a panel including Napsin A, Caveolin-1, and Tenascin-X significantly aids in the differential diagnosis of lung adenocarcinoma and epithelioid mesothelioma. While Tenascin-X provides valuable supplementary data, the clinical application of Type III Collagen is constrained by its low sensitivity. Integrating these markers into diagnostic protocols can enhance diagnostic accuracy, though further validation in larger cohorts is recommended.