ECP 2023 Abstracts

S155 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 breast cancer (BC). This study aims to determine interobserver agree- ment between pathologists using the International TILs Working Group recommendations for the assessment of stromal TILs (sTILs) in BC. Methods: We retrospectively analysed 53 hematoxylin and eosin stained slides of invasive BC, obtained from 26 core needle biopsies and 27 surgical resections. Three pathologists independently reviewed each slide and evaluated sTILs. We used Fleiss’s kappa statistics to calculate the overall proportion of interobserver agreement. Results: The mean of age was 56.5 years. The kappa statistic for sTILs assessment was 0,55 with 15 discrepancies cases. Discordances were mostly noted in surgical resection specimens (37%) compared to micro-biopsies (19%) and interested mainly TILs proportions in intervals (5-10%) and(40-50%). In operative specimen, discrepancies reasons included the difficult distinction between lymphocytes and granulocytes in one side and carcinomatous cells and lymphocytes on the other side. In all samples, there has been a tendency to increasing TILs average rates in the presence of a focal hot spot zone. Artefac- tual retraction spaces helped to distinguish carcinomatous clusters from stromal inflammatory infiltrate. A weakly contrasting staining increases difficulties to distinguish carcinomatous cells from inflam- matory cells. Conclusion: Acceptable agreement in sTILs assessment was noted when applying the international TILs Working Group recommenda- tions. Sample fixation quality, which is better in micro-biopsies speci- men, and a suitable contrasting staining, play an important role in the distinction between cell types. E-PS-02-012 Nonnecrotising granulomatous lymphadenitis in the context of autoimmune pseudosarcoidotic reaction S. Blasco Muñoz*, A. Sánchez Espinosa, A. Ortiz González, E. Guillén Saorín, D. Pérez Parra, C.A. Capozzi, J.M. Acosta Ortega, M.J. Sánchez de las Matas Garre *Complejo Hospitalario Universitario de Cartagena, Spain Background & objectives: A 36-year-old woman with non-special infiltrating carcinoma (NOS) in the right breast, hormone receptor-neg- ative and HER2-neu positive, associated with intraductal component; and tubular carcinoma in the left breast, hormone receptor-positive and HER2-neu negative. Methods: In PET-CT, in addition to the breast tumour tissue, multi- ple axillary, right supra and infraclavicular, right internal mammary, mediastinal, bilateral hilar, presacral/behind the psoas, left obturator and intergluteal lymphadenopathies are evidenced. Treatment with Pertuzumab-Trastuzumab-Docetaxel-Zometa was started. Given the persistence of mediastinal and inguinal adenopathies after completing treatment, it was decided to perform a biopsy. Results: In both biopsies representative fragments of lymph nodes (structures with capsule and secondary follicles) were confirmed, with abundant medium and large sarcoidosis-like granulomata (naked lym- phohistiocytic aggregates with some multinucleated giant cells). No signs of malignancy were observed. Immunohistochemical techniques with CK AE1-AE3 were performed without identifying metastases. A diagnosis of sarcoid granulomatous lymphadenitis is proposed. Recently a new lesion has appeared in the spleen, which has been biopsied, find- ing the same histological features of non-necrotizing granulomatous reaction. Conclusion: Sarcoidosis-like reactions have been described in 4-14% of cancer patients and occur more frequently in patients receiving Trastuzumab treatment. Distinguishing these lesions from metastases is complicated without a biopsy, but necessary, as it can avoid over- treatment of patients. It should especially be suspected in patients in whom chemotherapy reduces tumour size but lymph nodes remain enlarged. E-PS-02-013 Artificial intelligence-based breast cancer detection facilitates auto- mated prognosis marker assessment using multiplex fluorescence immunohistochemistry N. Blessin*, T. Mandelkow, E. Bady, M. Lennartz, A. Lebeau, S. Steurer, E. Burandt, T.S. Clauditz, G. Sauter, M. Graefen, S. Minner, C. Bernreuther *Institute of Pathology, University Medical Center Hamburg-Eppen- dorf, Germany Background & objectives: Prognostic markers in routine clinical prac- tice of breast cancer are often assessed using RNA based multi-gene panels that are depending on a fluctuating tumour purity. Multiplex fluorescence immunohistochemistry (mfIHC) holds the potential for improved risk assessment. Methods: To enable automated prognosis marker quantification, we have developed and validated a framework for automated breast cancer detection involving three different artificial intelligence analysis steps and an algorithm for cell-distance analysis using BLEACH&STAIN multiplex fluorescence immunohistochemistry. Pan-cytokeratin (panCK) antibodies were used to detect epithelial cells and antibod- ies directed against Myosin and p63 were used to identify basal cells. Results: The optimal distance between Myosin+ and p63+ basal cells and benign panCK+ cells was identified as 25 μm in breast cancer and used – combined with deep learning-based algorithms – to exclude benign glands from the analysis. Our framework discriminated normal glands from malignant glands with an accuracy of 98.4% (95% confi- dence interval [CI]: 97.4 – 99.3). The approach for automated breast cancer detection improved the predictive performance of several prog- nosis markers significantly (each p<0.05) and a comparison with manu- ally assessed data using conventional brightfield immunohistochemistry showed a high concordance for a multitude of different prognosis marker such as PR, ER, GATA3, HER2, and PD-L1 (each <0.0001). Conclusion: The combined assessment of up to 5 markers in a prog- nosis score showed strong prognostic relevance (p<0.001) and was an independent risk factor in multivariate analysis (p=0.005). Thus, the data from this study show that automated breast cancer detection in combination with artificial intelligence-based analysis of multiplex fluorescence immunohistochemistry enables a rapid and reliable analy- sis of multiple prognostic parameters. The major advantage of this method is the analysis of malignant cells exclusively that cannot be achieved using RNA-based panel analysis. E-PS-02-014 Androgen receptors in metastatic triple negative breast cancer J. Boavida*, I. Pinho*, T. Barroso, V. Patel, L. Gonçalves, R. Lopes Brás, M. Esperança Martins, M. Pinho, R. Moiteiro da Cruz, R. Teix- eira de Sousa, L. Correia, L. Costa *Serviço de Anatomia Patológica, Centro Hospitalar Universitário de Lisboa Norte, Faculdade de Medicina da Universidade de Lisboa, Portugal*Department of Medical Oncology, Hospital de Santa Maria, CHULN, Portugal Background & objectives: Triple-negative breast cancer (TNBC) expresses androgen receptors (AR) in up to 30% of cases. ARs are emerging biomarkers in metastatic TNBC (mTNBC). We aimed to evaluate the expression of ARs in mTNBC patients and correlate it with overall survival (OS). Methods: Retrospective cohort study of mTNBC patients, with tis- sue sample at our Pathology Department, between 2017-2021. Demo- graphic, clinicopathological and treatment data were gathered from records. AR expression was assessed immunohistochemically in sam- ples prior to systemic treatment, evaluated independently by two pathol- ogists (considered positive if ≥1% of tumour cells stained). 23 patients