ECP 2023 Abstracts

S102 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Methods: From October 2020-December 2022; 31 FNAC cases of metastatic breast carcinoma -devoid of cell blocks- were retrospectively analysed and compared with synchronous breast mass CNB results. All cases were prepared via Liquid Based Cytology technique (SurePath- BD). ER and CerbB2 antibodies were applied to Papanicolaou stained slides by Ventana. Statistical analysis was performed by using SPSS. Results: Examination of the slides revealed that, nine of 31 cases were negative and 22 were positive for ER. For CerbB2, two cases were inadequate for interpretation. Fifteen cases were negative (Score 0/1+), 5 cases equivocal (Score 2+) and 9 positive (Score 3+/Ampli- fication identified via in-situ hybridization). When all the FNAC data were compared to CNB, the positive predictive value (PPV) of ER was 100%; negative predictive value (NPV) was 66.7%. For CerbB2, PPV was 77.8%; NPV was 93.3%. Consequently, the sensitivity of ER and CerbB2 were 88%, 87.5%, respectively (p<0.001). The specificity of ER and CerB2 were 100%, 90.5%, respectively (p<0.001). Conclusion: The results of our study showed that FNAC is an efficient and accurate method both in the diagnosis and evaluation of ER and CerbB2 status in metastatic axillary lymph nodes in patients with breast cancer. PS-16-008 Rapid toluidine blue staining for on-site evaluation of cytological specimens: the Lausanne experience C. Royer*, M. Maillard, E. Dubruc, E. Hewer *CHUV Lausanne, Switzerland Background & objectives: Rapid toluidine blue staining for on- site evaluation (ROSE) of cytological specimens takes less than a minute, while offering excellent morphology. Here, we assess the performance of ROSE using toluidine blue staining in our institution and illustrate its morphological characteristics. Methods: We evaluated a series of consecutive thyroid, lung, head and neck FNA specimens with ROSE performed for assessment ade- quacy, for triage for ancillary testing and/or for preliminary diagnosis. Additionally, we illustrated the morphological features identified in toluidine-blue stained slides as compared to the definitive Papani- colaou staining. Results: Adequate material was obtained in 110 of 118 (93.2%) con- secutive samples. In only a single case (0.8%), ROSE had erroneously suggested an adequate specimen. In 4 samples (3.3%), the specimen was inadequate according to ROSE, but adequate according to the final evaluation. Among the 106 specimens with adequate material on both ROSE and definite evaluation, both were positive in 47 samples (39.8%), both were negative in 40 samples (33.9%). For 2 samples (1.7%) tumour cells were not identified during ROSE, but present in the definite samples, corresponding to 100% specificity and a 95.8% sensitivity of the ROSE. Evaluation for the presence of neoplastic cells was deferred for 5 samples (4.2%). Conclusion: The previously described rapid toluidine blue staining protocols allows for reliable ROSE of thyroid, head and neck, and pulmonary FNA specimens with high concordance between rapid and final evaluation and in particular without risk of false positive ROSE. The staining protocol provides excellent nuclear morphology, very similar to a Papanicolaou staining. As the staining is non-permanent, it is fully compatible with subsequent Papanicolaou staining of the same slides. PS-16-009 The value of p16/Ki-67 double staining in the diagnostic triage of the abnormal Pap test S. Stemberger-Papic*, D. Vrdoljak-Mozetic, D. Versa Ostojic, R. Rubesa-Mihaljevic, M. Dinter *Department of Pathology and Cytology, Clinical Hospital Centre Rijeka, Department of Pathology, Medical Faculty, University of Rijeka, Croatia Background & objectives: Dual p16/Ki-67 immunocytochemical staining is used for the detection of the HSIL that require further treat- ment. The aim of this work is to evaluate the value of p16/Ki-67 as a predictive marker in patients with ASCUS, LSIL and ASC-H cytology. Methods: 312 samples of conventional cytology were analysed and p16/ Ki-67 double staining (CINtec PLUS, Roche, Switzerland) was per- formed on the same smear. The results were compared with the findings of histological examinations (conization, LLETZ, biopsy and endocervi- cal curettage) or with clinical follow-up of patients for at least 12 months. Results: p16/Ki-67 staining was positive in 154 (49.4%) samples. In the p16/Ki-67 positive group, 83(53.9%) HSIL+ lesions were confirmed, and in the p16/Ki-67 negative only 10(6.3%). In the ASCUS category, out of 133 samples, 39(29.3%) were p16/Ki-67 positive and 4(10.3%) HSIL+ lesions were detected. In the LSIL category 37 samples was analysed, p16/Ki-67 was positive in 14(37.8%) and HSIL+ lesions were confirmed in 4(28.6%). In the ASC-H group, 142 samples were analysed, p16/Ki-67 were positive in 101(71.1%) and 75(74.3%) HSIL+ lesions were confirmed. Based on the correlation of p16/Ki-67 and histology or clinical follow- up, an overall sensitivity, specificity, positive and negative predictive value were 89.3%, 67.6%, 53.9% and 93.7%. respectively. Conclusion: The results of the study show a high negative predictive value of p16/Ki-67 immunocytochemical staining in the detection of HSIL+ lesions in patients with ASCUS, LSIL and ASC-H cytology. The use of p16/Ki-67 staining could lead to more accurate and efficient man- agement of patients with abnormal Pap test results, potentially reducing the need for unnecessary interventions and improving patient outcomes. PS-16-010 Comparison of risk of malignancy and predictive value of diag- nostic categories defined by Papanicolaou Society of Cytopathol- ogy System and WHO Reporting System for Pancreaticobiliary Cytopathology in solid pancreatic lesions B. Vasas*, A. Fábián, Z. Bősze, S. Hamar, L. Kaizer, P. Bacsur, T. Resál, K. Farkas, T. Molnár, R. Bor, Z. Szepes *University of Szeged, Department of Pathology, Hungary Background & objectives: The standardized diagnostic categories defined by the new WHO Reporting System support the interdisci- plinary interpretation of cytological findings in the management of pancreatic cancer. Methods: Aim of the study was to compare this classification to the Papanicolaou Society of Cytopathology (PSC) system in terms of predic- tive value and risk of malignancy (ROM) in solid pancreatic lesions. All consecutive patients with solid pancreatic lesions were retrospectively enrolled who underwent endoscopic ultrasound-guided fine-needle aspi- ration (EUS-FNA) sampling in University of Szeged from 2014 to 2021. Results: 521 EUS-FNA samplings were performed with a malignancy rate of 81.76%. In both systems, the ROM of “non-diagnostic”, “nega- tive for malignancy”, “atypical”, “suspicious for malignancy” and “malignant” categories were 48.2%, 2.3%, 78.1%, 100.0% and 99.4%. Despite the heterogeneous “neoplastic: other” category of PSC system, the ROM for solid lesions was 100%. PaN-high including only 2 endo- sonographically solid cases of high-grade IPMNs showed 100% ROM. There were no differences between PSC and WHO systems in sensitiv- ity, specificity, NPV and PPV: excluding the “atypical” category, these were 99.7%, 95.6%, 97.7%, 99.5%. “Atypial” category considered as benign resulted in higher decrease in validity compared to “atypical” considered as true malignant (93.6% vs. 97.7%). Conclusion: For solid pancreatic lesions, the WHO system was identi- cal to the PSC system in terms of ROM and predictive values. This work was supported by the research grants of the National Research, Development and Innovation Office (Grant ID: 125377, 129266 and 134863), by the New National Excellence Program of the Ministry of Human Capacities (UNKP-21-5-SZTE-552 to FK, UNKP- 22-5-SZTE-545 to BR, UNKP-22-4-SZTE-296 to FA) and Janos Bolyai