ECP 2023 Abstracts

S374 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 cancer (PCa) patients of different Gleason scores compared to benign prostate hyperplasia (BPH). Methods: PDL-1 expression was evaluated immunohistochemically using SP142C-terminal Recombinant Anti-PD-L1 monoclonal antibod- ies (Abcam). Marker expression was determined to be positive for mod- erate or severe immunolabeling in at least 1% or 10% of neoplastic cells or associated immune cells. We then established the relationship between marker expression and available clinical and pathological parameters: patient age, Gleason score, prognostic group grade, tumour stage. Results: PDL-1 expression was higher in the PCa group compared to cases diagnosed with BPH. Also, the PDL-1 expression was cor- related with the Gleason score, but not with the other parametrically evaluated ones. Conclusion: The value of PDL-1 is strongly expressed in prostate can- cers, unlike non-tumour prostate lesions and correlates with the Glea- son Score, which highlights a potential independent prognostic role in prostate cancer, with a role in the therapeutic management of patients. E-PS-24-029 Neoplastic transformation of prostatic tissue is accompanied by alteration in protein sialylation A. Janegova*, P. Babal, P. Janega *Institute of Pathological Anatomy, Comenius University in Bratislava, Slovakia Background & objectives: Prostate cancer is a common malignancy in men, there is no reliable screening test for early detection. Altered sialylation is often seen in cancerous tissues, including prostate tissue. This study investigates changes in sialic acid expression in prostatic adenocarcinoma. Methods: The study analysed tissue samples from 120 patients with benign prostatic hyperplasia and prostatic adenocarcinoma of various Gleason scores (ISUP Grade Group 1-5) using lectin fluorescent histo- chemistry to evaluate sialic acid expression. Quantitative changes were analysed through morphometric analysis, using sialic acid-specific lec- tins, specific for alpha-2,3 linkage Maackia amurensis leukoagglutinin and alpha-2.6 linkage Sambucus nigra agglutinin. Results: In prostatic tissue, the majority of sialic acid positivity is attributed to alpha-2,6 linkage. However, neoplastic transformation results in a significant decrease of alpha-2,6 sialylation in affected glands, which is more pronounced in adenocarcinomas with higher Gleason scores. Conversely, no significant changes were observed in alpha-2,3 sialylated glycoconjugates. There were no significant changes observed in the expression of sialic acid in stromal cells. Conclusion: Alterations in sialic acid expression are linked to the development of malignancies, which can affect the behaviour of neo- plastic cells such as their survival, invasiveness, and metastatic poten- tial. The evaluation of changes in sialic acid expression in prostatic tissue can provide insights into the malignant potential of prostate cancer, one of the most common malignancies in men. Understanding these changes is crucial for the development of new diagnostic and therapeutic strategies. Funding: APVV 20-0243 and VEGA 1/0684/21 E-PS-24-030 Primary poorly differentiated carcinoma in seminal vesicle Y. Jang* *Ewha Womans University Medical Cent, Republic of Korea Background & objectives: Primary seminal vesicle carcinoma is an extremely rare and poor prognostic tumour. Here, we reported a poorly differentiated carcinoma of the primary seminal vesicle. Methods: Here, we present a case of a 63-years-old man with intermit- tent haematuria. A Magnetic Resonance Imaging (MRI) scan revealed lobulated mass of the right seminal vesicle (3.8cm). The serum prostate specific antigen (PSA) and serum cancer antigen 125 (CA125) level were within the normal range(PSA, 0.11 ng/mL; CA125, 6.3 ng/mL) Results: Radical prostatectomy was performed. Microscopically, the right seminal vesicle showed poorly differentiated invasive carcinoma with solid pattern and extensive necrosis. Immunohistochemically, the tumour was positive for high molecular weight cytokeratin, cytokeratin 7 and can- cer antigen 125 and negative for cytokeratin 20, prostate specific antigen and NKX3.1. After operation, he received additional radiotherapy. Cur- rently, he is well with no signs of recurrence at 20 months after operation. Conclusion: The seminal vesicle carcinoma is very rare, and only a few have poorly differentiated, with poor prognosis. We share its micro- scopic characteristics and immunohistochemical staining of rare case. E-PS-24-032 MALT/extranodal marginal zone lymphoma of urinary bladder E. Koniaris*, M. Sevastiadou, A. Aktselis, G. Kafiri *Pathology Departmant, General Hospital of Athens ’Hippocratio’, Greece Background & objectives: Extranodal marginal zone (EMZ) lym- phoma of urinary bladder/MALT, is an extremely rare entity in the urinary bladder, affecting females, representing less than 0,2 % off all malignant urinary bladder neoplasma and about 60 cases have been reported in the literature. Methods: An 84-year-old patient admitted to our hospital with cystitis and haematuria and transurethral cystoscopy was performed. Endo- scopically, a broad-based elevation of the cystic wall was observed and resection of the tumour was performed and send for biopsy in our department. Macroscopically, the tissue had brownish hue, fibroelastic consistency and measured 3,5X3X0,8 cm. Results: Microscopically, the tissue specimens were almost completely infiltrated by monomorphic, small and medium sized B lymphocytes, which were CD20 positive. The Lymphocytes had irregular nuclei, many with nucleolus and scanty cytoplasm. The neoplastic cells had a diffuse and/or partly nodular growth pattern, with scattered, reac- tive collonized lymphoid follicles and presence of atrophic germinal centres. On immunohistochemical (IHC) examination with cytokeratin AE1/AE3, we recognized lymphoepithelial lesions within the neoplas- tic cells. The lesion infiltrated the part of the muscular wall of the urinary bladder that was also resected. Other IHC findings included positivity of bcl2, ki67 (40-45%) and MUM-1 (30-35%). CD10, bcl6, CD3. PSA, CD5, CD23, were evaluated as negative. Conclusion: EMZ lymphomas of the urinary bladder are extremely rare low grade extranodal B-cell lymphomas, with excellent general prognosis, mainly affecting female patients and have been strongly associated with recurrent episodes of infectious cystitis (like E. coli). There are plenty of treatment modalities including: a) observation based on risk factors (age, grade, etc), b) surgical resection (complete excision or biopsy), c) radiation, alone or following biopsy, d) chemo- therapy, in systemic cases and e) targeted antibody therapy, with rituxi- mab (anti-CD20 antibody). E-PS-24-033 Prolaris kit cell-cycle risk scores are reproducible across external molecular and pathology laboratories M. Kornilov*, V. Kuhl, W. Clegg, B. Mabey, J. Lehmann-Che, J. Champ, R. Fattouh, K. Boissinot, F. Moinfar, S. Ratzel, S. Delee, J. Doedt, R. Kronenwett *Myriad International, Germany Background & objectives: The Prolaris test predicts the risk of prostate cancer aggressiveness. The Prolaris kit was developed and validated to be used as a decentralized solution. Here, we assessed the Prolaris kit cell-cycle progression score (CCP) reproducibility across three different laboratory sites.