Pancreatic ductal adenocarcinoma (PDAC) frequently requires neo-adjuvant therapy, leaving cytologic preparations-especially endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) smears-as the only naïve tissue available for molecular testing. However, their applicability remains underappreciated due to limited data and concerns about specimen adequacy. This study aimed to evaluate the feasibility of performing molecular analysis on cytologic smears to detect targetable alterations in PDAC. Molecular analysis was conducted on 120 PDAC samples: 41 cytology specimens, 50 core biopsies, and 29 resections. KRAS mutations and homologous recombination repair gene alterations were assessed. Rapid on-site evaluation (ROSE) guided triage in all FNA cases. DNA and RNA isolation were performed, followed by quality control (QC) assessment and sequencing. DNA isolation succeeded in 92/95 cases (97%), with a 100% success rate in cytologic specimens. RNA isolation passed QC in 71/84 samples (83%), with failures more common in smears (n=8). KRAS mutations were detected in 71/85 patients (82%), with the highest detection in cytologic specimens (92%) compared to biopsies (78%) and resections(80%). Molecular testing is feasible and may even be more successful in cytologic smears than in biopsies or resections. High diagnostic yield and rapid processing favor their integration into routine molecular workflows. The superior performance of smears may relate to reduced stromal content and minimal processing delays. Cytologic specimens showed 100% DNA QC success, even when RNA QC failed, supporting their reliability. Although RNA analysis had a modest failure rate, its overall success suggests it can be incorporated into routine testing, particularly as fusion-driven targets gain clinical relevance.

Malignant pleural effusion is a frequent manifestation in cancer patients, with effusion cytology playing a vital role in diagnosis and subtyping. Present study evaluated the effect of sample volume on malignancy detection and estimated the risk of malignancy (ROM) by using the International System for Reporting Serous Fluid Cytopathology (TIS). Pleural effusions submitted from May 2021 to December 2022 were reclassified using the International System for Reporting Serous Fluid Cytopathology (TIS) into five categories: non-diagnostic (ND), negative for malignancy (NFM), atypia of uncertain significance (AUS), suspicious for malignancy (SFM), and malignant (MAL). Risk of malignancy (ROM) and performance metrics were calculated based on follow-up histology and/or repeat cytology, ancillary tests and clinico-radiology. Volume data from 493 samples were grouped into six bins (0-10 mL to >300 mL), and malignancy fractions were analysed. Generalized Estimating Equations (GEE) logistic regression assessed the impact of volume, sex, and age on diagnostic outcomes. Analysis was performed in R. Of 1265 samples from 1107 patients, 875 (69.2%) had follow-up data. ROM estimates were: ND 23.6%, NFM 11.6%, AUS 57.1%, SFM 100%, MAL 97.5%. MAL samples had significantly higher median volume than NFM (100 vs 35 mL; p<0.000). False negatives had lower volumes than true positives (50 vs 80 mL; p=0.027). Malignancy detection was lowest in samples <10 mL (7.4%) and highest in >300 mL (40.4%). Volumes <25 mL were significantly associated with reduced odds of malignancy detection (p<0.05). Sample volumes <25 mL are linked to lower malignancy detection, underscoring the importance of adequate volume and supporting TIS implementation in routine cytology.

Background Blastemal tumours are quite frequent malignancies in childhood. In many oncological centres, fine needle aspiration is a part of the specific diagnostic procedure. In this review, the cytological features of the most common entities - i.e., neuroblastic tumours, nephroblastomas, retinoblastomas and hepatoblastomas - are covered. Summary Blastemal tumours are composed of blastemal cells, which are frequently rounded or oval. This morphological similarity among different entities requires detailed clinical and radiological information for accurate diagnosis. Cytological specimens play a crucial role, especially when histological specimens are not available or in cases where a prompt initiation of treatment is needed. Key messages Cytological smears are highly cellular and show specific patterns for accurate histological typing. The hypercellularity of cytological specimen allows for the use of high-quality material for ancillary techniques, which are important for assessing several prognostic factors.

Introduction: Paediatric breast lesions are rare and mostly benign. Despite their benign nature, the presence of these lesions in this population often raises concerns. Fine-needle aspiration biopsy (FNAB) offers a minimally invasive, though its application in paediatric populations remains debated due to interpretative challenges. This systematic review aims to assess the utility, limitations, and diagnostic performance of FNAB in the evaluation of paediatric breast lesions. Methods: A systematic search was performed in PubMed for articles published from January 2014 to February 2025. Non-humans and non-English language reports were excluded. Based on title and abstract screening, 25 articles were selected, and 13 additional articles were retrieved through reference list, yielding a total of 38 studies for qualitative analysis. Data were manually extracted and synthesized. Results: Benign lesions represented the majority of cases, with fibroadenomas being the most frequent (65%–95%), followed by benign phyllodes tumours, hamartomas, tubular adenomas, pseudoangiomatous stromal hyperplasia (PASH), and cystic lesions. Malignant lesions were rare and included metastatic tumours, malignant phyllodes tumours, secretory carcinoma, and primary breast sarcomas. FNAB demonstrated high diagnostic accuracy for benign lesions but showed limitations in distinguishing benign from malignant tumours. ROSE was identified as a valuable adjunct, improving sample adequacy, reducing the rate of inconclusive results, and enhancing diagnostic reliability. Conclusion: FNAB is an effective first-line diagnostic modality for paediatric breast lesions, offering high accuracy for benign conditions. However, limitations exist in discriminating borderline and malignant lesions, warranting correlation with clinical, radiological findings, and, in some cases, core biopsy confirmation. The integration of ROSE enhances FNAB diagnostic yield and may further refine management strategies. A multidisciplinary approach remains essential to ensure optimal, minimally invasive care for paediatric patients.

Spindle cell lesions in the head and neck often mimic sarcomas but may include a wide range of benign and malignant entities. Fine needle aspiration (FNA) is a minimally invasive method used to evaluate such lesions, though cytological interpretation can be challenging due to overlapping features. This retrospective study included 12 primary spindle cell lesions of the head and neck, selected based on inclusion/exclusion criteria. Papanicolaou and May-Grünwald-Giemsa stains were used for smear evaluation. Cell blocks were prepared, and cytological diagnoses were compared with histopathological outcomes. The 12 cases were diagnosed as follows: nodular fasciitis (n=2), schwannoma (n=2), malignant peripheral nerve sheath tumor (n=1), leiomyosarcoma (n=1), liposarcoma (n=1), rhabdomyosarcoma (n=1), osteosarcoma (n=3), and chondroblastoma (n=1). Cytological features showed moderate correlation with final histology. FNA is a valuable, cost-effective tool for evaluating spindle cell lesions in the head and neck. While morphological overlap poses diagnostic limitations, ancillary techniques and molecular studies enhance its accuracy and clinical utility.

Renal cell carcinoma frequently metastasizes to multiple sites, which often poses significant diagnostic challenges, particularly when the primary tumor is unknown or occult. This retrospective study analyzed 43 fine-needle aspiration (FNA) cases of metastatic ccRCC from a single institution to characterize metastatic patterns and evaluate the diagnostic utility of cytology combined with immunocytochemistry. We retrospectively reviewed FNA cases diagnosed as metastatic RCC from January 2003 to December 2024. Cytopathological evaluation included cellularity, architectural patterns, cytoplasmic and nuclear features, background elements, and immunocytochemical analysis when available. Cytology demonstrated excellent diagnostic performance. The majority of cases were reported as Malignant (91%), while the remaining 9% were classified as Suspicious for Malignancy (SFM) or Atypia of Undetermined Significance (AUS). Notably, in 42% of cases, FNA established the initial diagnosis of RCC, highlighting its value in detecting occult primary tumors. Diagnostic accuracy relied on cytomorphologic evaluation, complemented by immunocytochemical profiling, which was performed on cell blocks in 60.4% of cases. Key markers such as PAX8, CD10, and RCCma were critical in confirming renal origin and differentiating ccRCC from morphologically similar neoplasms in each organ. FNA cytology, corroborated by focused immunocytochemistry, plays a key role in diagnosing metastatic ccRCC, particularly when the presentation is uncommon or the primary tumor is hidden. This integrated method supports effective clinical management, avoiding unnecessary surgery in cases that may benefit from systemic therapy.

Oral squamous cell carcinoma (OSCC) is the most prevalent oral malignant neoplasm. Cytopathology may represent an important tool in the screening of OSCC, and liquid-based oral brush cytology (LBOBC) has been widely studied because of its clearer cell sample results. These cytopathological analyses could be more efficient with the aid of artificial intelligence (AI). The objective of this study was to analyze the effectiveness of two AI models (Papanicolaou and AgNOR Slide Image Examiners) in LBOBC analyses. Two human evaluators and the AI models performed cell maturation pattern analysis and mean nucleolar organizer region (NOR) per nucleus count in Papanicolaou and silver-stained nucleolar organizer region (AgNOR) oral cytopathological samples of 20 individuals, respectively. Inter-evaluator agreement was evaluated by kappa and intraclass correlation coefficient (ICC). Chi-square and Wilcoxon matched-pairs/Friedman tests analyzed differences between the conventional and LBOBC methods, and among evaluators. Kappa between the Papanicolaou AI model and each human researcher was substantial (k = 0.69) for the conventional method, and moderate for the LBOBC (k = 0.55-0.53. There were statistical differences in the cellular type analysis between cytology methods and among evaluators (p < 0.001). The automated AgNOR model showed an excellent/highly good agreement with human evaluators for NOR count in both cytology methods, with and without bounding boxes. There was no statistical difference in the NOR count between methods (p > 0.05). In the conventional method, there were differences among evaluators (p < 0.05); in the LBOBC, there were not (p > 0.05). The AgNOR automated model is reliable when assessing NOR count in oral samples processed by different cytological methods, when compared to the human analysis. The Papanicolaou model still needs more training with LBOBC samples.