This study aimed to elucidate the spectrum of clinical manifestations, cytomorphology, immunophenotype, and the molecular genetic features of lymphoblastic lymphoma/acute lymphoblastic leukemia (LBL/ALL) in the context of serous effusions (SE). A retrospective analysis evaluated the cytomorphological features, immunophenotype, and the cyto-histological correlations of twenty-one LBL/ALL associated with SE. Concurrently, bone marrow (BM) aspiration samples were analyzed using an integrated approach, including flow cytometry, reverse transcription PCR (RT-PCR), next-generation sequencing (NGS), or whole transcriptome sequencing (WTS). Of the 21 cases of SE LBL/ALL, 16 cases were T-LBL/ALL and 5 cases were B-LBL/ALL. The cases included 17 pleural, 2 peritoneal, and 2 pericardial fluid samples. Both T-LBL/ALL and B-LBL/ALL in SE exhibit a blast-like morphology, characterized by small to medium size, irregular nuclear membranes, and inconspicuous nucleoli, alongside frequent nuclear fragmentation and apoptotic bodies. LBL/ALL express immaturity markers such as terminal deoxynucleotidyl transferase (7/17, 41.2%), CD10 (6/12, 50%), CD43 (8/8, 100%), and CD99 (6/6, 100%). T-LBL/ALL and B-LBL/ALL specifically express T-cell markers (CD2 [3/6, 50%], CD3 [10/12, 83.3%], CD5 [2/11, 18.2%], CD7 [10/10, 100%]) or B-cell markers (CD20 [3/5, 60%], CD79a [4/4, 100%], PAX5 [5/5, 100%]), respectively. A high proportion of primitive and immature lymphocytes exceeding 25% in BM was observed in T-LBL/ALL (5/7) and in one case of B-LBL/ALL. No BCR/ABL gene rearrangements were detected in any cases. Furthermore, fusion gene MLL::ENL and PLCALM::MLLT10, as well as mutations in genes including WT1, NOTCH1, PAX5, IKZF, ARID1A, BCOR, SETD2, ARID2, TET2, JAK3, NF1, and CEBPA, were identified in LBL/ALL through RT-PCR, NGS, or WTS analyses. The integration of clinical manifestations, cytological evaluation, and gene expression profiles is instrumental in achieving accurate diagnosis, subclassification, and prognosis of LBL/ALL within the context of SE.

Introduction: Fine-needle aspiration biopsy (FNAB) is a minimally invasive diagnostic method widely used in the evaluation of lymphadenopathies. However, there are few studies evaluating its applicability in different age groups, especially among the pediatric population. This study aimed to evaluate the cytological findings of lymph nodes FNAB between pediatric and adult patients using the WHO Reporting System for Cytopathology of Lymph Nodes, Spleen. Methods: This retrospective and observational study included 366 cases of lymph node FNAB collected and analyzed by a single pathological center (the Instituto de Patologia de Araçatuba), Brazil, from January 2016 to December 2024. Cytological diagnoses were categorized using the WHO Reporting System for Cytopathology of Lymph Nodes, Spleen, and Thymus into five categories (inadequate/insufficient, benign, atypical, suspicious for malignancy, and malignant) and correlated with histopathological outcomes, when available. Ancillary techniques and rapid on-site evaluation were not available. Statistical analyses included chi-square and Fisher’s exact tests. p < 0.05 was considered statistically significant. Results: Among the 366 cases, 17 (4.6%) were pediatric and 349 (95.4%) were adult. The most frequent location of the lesions was the head and neck region (79%). Benign cytological diagnoses were significantly more common in children (94.1%), while suspicious for malignancy and malignant results were exclusive to adults (29.3% and 14%, respectively; p = 0.001). Larger lymph nodes (>2 cm) were significantly associated with malignancy (p < 0.0001). Considering the total population, the rates of risk of malignancy (ROM) were 50% for category “insufficient,” 32.6% for benign, 82.8% for suspicious, and 97.5% for malignant cases. From each category, 28 (53.8%), 49 (27.7%), 35 (71.4%), and 16 (32.6%) patients were underwent histopathological follow-ups, respectively. Conclusion: This study, despite the limited pediatric sample, demonstrates that the method is applicable to both pediatric and adult patients, including those outside cancer centers. The calculated ROM was 50% for inadequate, 32.6% for benign, 82.9% for suspicious, and 97.6% for malignant categories. Deviations from WHO reference intervals for inadequate and benign cases may be attributed to the absence of ancillary techniques. Then, two main findings emerged: (i) benign cytological diagnoses predominated in children, while suspicious and malignant results occurred exclusively in adults; and (ii) lymph nodes >2 cm were strongly associated with malignant cytological and histological outcomes.

Introduction: Urine cytology is a noninvasive and widely used approach for the early detection of urothelial carcinoma (UC), but its diagnostic accuracy is limited, particularly for low-grade lesions. This study aimed to develop a novel artificial intelligence (AI)-based framework for risk stratification of UC from whole-slide images (WSIs), offering a promising solution to enhance the diagnostic accuracy of urine cytology. Methods: A total of 385 urine cytology slides were included and stratified into three diagnostic groups based on cytological evaluation: negative for high-grade urothelial carcinoma (NHGUC), low risk (including atypical urothelial cells and low-grade urothelial carcinoma [LGUC]), and high risk (including suspicious for high-grade urothelial carcinoma and high-grade urothelial carcinoma). Following digitization into WSIs, expert pathologists conducted detailed cell-level annotation. Cell detection and segmentation were performed using RTMDet and DuckNet, and the extracted features were aggregated into slide-level representations for training and evaluation of classification models. Results: Support vector machine demonstrated the highest overall performance among the classifiers, with an accuracy of 79%, recall of 79%, and a specificity of 90%. The model demonstrated strong classification performance across three risk stratifications. The high-risk group achieved a sensitivity of 73.1% and specificity of 90.2%, while the low-risk group showed a sensitivity of 81.8% and specificity of 89.1%. Precision-recall curves indicated that the NHGUC group achieved the highest average precision, reaching 0.93, followed by the high-risk group at 0.85 and the low-risk group at 0.82. ROC analysis further demonstrated strong discriminative capability for three risk groups, with the area under the curve measured at 0.95 for NHGUC and 0.91 for both the low-risk and High-risk groups. Conclusion: The proposed AI-assisted framework shows robust and interpretable performance in stratifying UC cytological categories from WSIs. It holds strong potential as a supportive tool in urine cytology, especially in assisting with the diagnosis of high-risk UC cases.

Introduction: We aimed to investigate malignancy rates in atypia of undetermined significance (AUS) subcategories and their association with cytomorphologic and ultrasonographic features. Methods: A total of 201 thyroid nodules with AUS cytology that underwent surgical resection were analyzed, including 169 AUS-nuclear (AUS-N) and 32 AUS-other (AUS-O) nodules. Cytomorphological and ultrasonographic features, along with the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) and the European Thyroid Imaging Reporting and Data System (EU-TIRADS) classifications, were analyzed to assess the association between malignancy and AUS subcategories. Results: The overall risk of malignancy (ROM) for AUS nodules was 19.4%, with a significantly higher rate observed in the AUS-N subgroup compared to AUS-O (21.9% vs. 6.3%, p = 0.04). A significantly higher ROM was observed in nodules with irregular margin, taller-than-wide shape, microcalcification, hypoechogenicity, and solid composition (OR = 9.63, 5.81, 3.33, 2.14, and 2.07, respectively). A statistically significant difference in ROM was observed across ACR-TIRADS and EU-TIRADS categories within the AUS nodules (p < 0.001 for both) and the AUS-N group (p = 0.001 and <0.001). A marked increase in ROM was observed with nuclear overlapping, pseudoinclusions, and enlargement (OR: 9.16, 4.47 and 2.80, respectively), while oncocytic atypia was associated with a reduced risk (OR: 0.44). In multivariate analysis, nuclear overlapping, pseudoinclusions, and sonographic irregular margins remained as independent predictors of malignancy (OR = 6.97, 6.09, and 5.79, respectively). Conclusion: To our knowledge, this is the first study to demonstrate a significant association between ACR-TIRADS classification and malignancy risk in the AUS-N subcategory.

Background: Fine-needle aspiration biopsy (FNAB) of lymph nodes is a widely used method for evaluating lymphadenopathy. FNAB offers general advantages of rapid turnaround time, low cost and minimal morbidity, and more specific advantages in various clinical situations, such as deeply located lymph nodes or patients with significant comorbidities. The FNAB sample can be utilized for a wide range of ancillary tests, including microbiological studies, immunocytochemistry for primary and metastatic neoplasms and flow cytometry immunophenotyping in cases of lymphoid-rich samples, where there is a suspicion for lymphomas. Summary: The increasing application of FNAB in lymph node pathology has led to the development of a standardized reporting system, formalized in the World Health Organization (WHO) Reporting System for Lymph Node, Spleen and Thymus Cytopathology (WHO System). This system is equally applicable to lymph node, spleen and thymus; however, this article focuses on lymph nodes. The WHO System was established through a joint project of the WHO, the International Agency for Research on Cancer (IARC) and the International Academy of Cytology (IAC) and is structured into five diagnostic categories: inadequate/insufficient/non-diagnostic, benign, atypical, suspicious for malignancy, and malignant. The WHO System provides a standardized and reliable means of categorizing various lymph node lesions based on cytopathology findings and enables pathologists to make more accurate and reproducible diagnoses, thereby improving clinical management and treatment decisions. Integrating cellular morphology and clinical-imaging data help distinguish benign from malignant lesions, significantly reducing diagnostic variability. The primary goal was to reduce diagnostic uncertainty and improve patient outcomes through greater consistency and clarity in lymph node cytopathology reports. The WHO System emphasizes the use of rapid on-site assessment (ROSE) to improve diagnostic accuracy and reduce the need for additional diagnostic procedures. The risk of malignancy (ROM) varies by diagnostic category, with higher risks of malignancy in the “Suspicious for malignancy” and “Malignant” categories. The system also includes recommendations for ancillary tests and performance of additional biopsies when further clarification is needed. The WHO System represents a significant advancement in the standardization of lymph node, spleen, and thymus cytopathology, facilitating interdisciplinary communication and improving risk stratification. However, diagnostic challenges remain, particularly in managing inadequate samples and interpreting atypical lesions, necessitating a multidisciplinary approach that integrates clinical, imaging, ancillary testing and, in some cases, core needle, or excision biopsy material. Key messages: The WHO System serves as a crucial tool for refining the diagnosis of the broad range of inflammatory, infectious, metastatic, and lymphomatous processes in lymph node pathologies. In addition, it is suitable for high income as well as most obviously low- and middle-income countries leading to optimizing therapeutic decision-making.

Introduction: The evaluation of lymph nodes (LNs) through fine needle aspiration (FNA) is widely used as the first-line approach in the assessment of unexplained lymphadenopathy due to its minimal invasiveness, speed, and cost-effectiveness and the availability of provide material for various auxiliary techniques. The Sydney Lymph Node Cytology Reporting and Classification System was introduced in 2020. The aim of our study was to classify LN-FNAs according to the Sydney System and to evaluate the concordance with histological diagnoses and the rates of malignancy in the available cases. Methods: Between 2019 and 2023, FNAs were retrospectively reviewed. A total of 1,000 cases were categorized according to the Sydney System as ND (inadequate/insufficient), benign, AUS/ALUS (atypical lymphoid cells of uncertain significance), suspicious, and malignant. The risk of malignancy was calculated for histopathological follow-up available cases. Results: Cases were categorized into 5 groups: 58 cases (5.8%) as “ND,” 560 cases (56%) as “benign,” 24 cases (2.4%) as “AUS/ALUS,” 32 cases (3.2%) as “suspicious,” and 326 cases (32.6%) as “malignant.” In the malignant group, 315 cases were metastatic malignancies and 11 were lymphoid malignancies. Histopathological follow-up was possible in 294 cases (29.4%). Among these, 159 were diagnosed as malignant. Of the malignant cases, 33 were diagnosed as lymphoma and 126 as metastatic malignancies. Based on the available data, the concordance rate between cytological and histological diagnoses was 81.0%. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated as 91.11%, 69.49%, 77.36%, and 87.23%, respectively. The risk of malignancy was 52.9% for the nondiagnostic, 12.7% for the benign, 33.3% for the atypical, 80.0% for the suspicious, and 77.3% for the malignant categories. Conclusion: The Sydney System is easily applied to LN-FNAs and shows a high cytology-histology diagnosis concordance rate and sensitivity. By simplifying reporting and strengthening communication between cytopathologists and clinicians, it enhances the clinical management of malignancy risk.