ECP 2023 Abstracts

S373 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Conclusion: We corroborate that, in our series of cases, the most fre- quent histological subtype of primary testicular lymphoma is DLBCL, and within this, the activated immunophenotype, according to the lit- erature reviewed. Early diagnosis and prophylaxis in the CNS is impor- tant for its prognosis. E-PS-24-025 Renal collision tumour composed of oncocytoma and clear cell renal cell carcinoma: case report and review of literature J.M. Gutiérrez Herrera*, H. Olauson, D. Chatzianastasiou, F. Jansson, D. Krantz *Karolinska University Hospital, Sweden Background & objectives: Collision tumours are rare and occur when two distinct neoplasms coexist together. Only limited data on their prognosis, immunohistochemical- and mutational profile is available. We characterized these features in a case of a renal collision tumour and reviewed the literature. Methods: Upon morphologic evaluation, both tumour types were fur- ther characterized immunohistochemically and with a broad next-gen- eration sequencing (NGS) cancer panel. For literature review, PubMed and Web of Science databases for renal collision tumours composed of oncocytoma and RCC were searched. Data collection was focused on morphologic characteristics, tumour stage, immunohistochemical profile and genetical aberrations. Results: We report an 83-year-old man with a left renal mass. Histo- logical evaluation revealed a pT3a kidney tumour consisting of a sarco- matoid clear cell renal cell carcinoma (sCCRCC) and oncocytoma. The tumour components bore distinct, characteristic immunohistochemi- cal profiles for their respective morphology. NGS analysis disclosed a PTEN mutation in the sCCRCC component, which was not present in the oncocytoma area. During follow-up, bilateral lung metastases were detected, which prompted radiotherapy and immunotherapy. To date, only two collision tumours composed of CCRCC and oncocytoma have been reported. To our knowledge, this is the first report of a PTEN mutation carrying, and immunohistochemically bona fide, collision tumour of CCRCC and oncocytoma. Conclusion: This report reveals an extremely rare renal collision tumour, with the novel finding of the CCRCC component to carry a PTEN mutation. Both components displayed their essential immuno- histochemical characteristics, which somewhat differs from the previ- ously reported case. Yet, this entity is diagnostically challenging and is important for pathologists to be aware of. Further studies are needed to determine the best treatment path for these tumours. E-PS-24-026 Bladder cancer in patients with spinal cord injury or neural tube defects: a retrospective study A. Hidalgo Romero*, Z. Calixto Alvarez, A. Diazgranados Daza, J. Chabla Jaramillo, I.M. de Torres Ramirez, S. Ramón y Cajal Agüeras, F. Lozano Palacio, M.E. Semidey Raven *Vall d´Hebron Barcelona Hospital, Spain Background & objectives: Spinal cord injury (SCI) or neural tube defects (NTD) patients have increased risk of developing bladder can- cer, with high grade/aggressive tumours and high mortality rate. Our aim is to describe morphological and outcome characteristics associ- ated with this patient population. Methods: A cohort of 10 cases of bladder carcinomas were selected with SCI/NTD from pathology files between 2007-2023. In each case, histomorphological features were collected, such as histological type, grade, carcinoma in situ presence, lymphovascular invasion and TNM stage. Clinical features such as age, gender, smoking habit, latent period, disease-free and overall survivals were included. Comparison between variables was done. Results: A series of 10 SCI/NTD patients were selected with blad- der carcinoma. The median age was 39 years (SD9,43). Nine patients (90%) were women. Four (40%) had smoke habit associated. Seven (70%) had congenital medullary injury and three (30%) had acquired injury: post-traumatic (2) and infectious (1). Latent period was >30y in six (60%) patients, 10-30y in two (20%) and <10 years in one (10%) patient. Histological subtypes were reported as squamous (80%) and adenocarcinoma (20%), high grade (100%) and infiltrative: >pT2 (90%), pT1 (10%). Three (30%) had lymph node metastasis and lym- phovascular invasion. Seven (70%) died in <1 year, two (20%) are alive after 10 years and 2 months, respectively. Conclusion: Bladder cancer in patients with SCI/NTD are high risk tumours that appear at an earlier age with advanced stage and poor outcome. Specific risk factors include indwelling catheters, urinary tract infections, bladder stones, and smoking history. Sur- veillance programs and early detection may require more invasive follow-up due to the atypical aggressiveness and lack of specificity of symptoms. Further research is needed to identify more reliable understanding of the disease in order to improve the outcome of these patients. E-PS-24-027 Mixed epithelial and stromal tumour: an exceptional tumour of seminal vesicle: a case report S. Hidouri*, M. Hamdani, M. Walha, C. Abdelhedi, K. Bouraoui, K. Bel Hadj Ali, A. Khabir *Department of Pathology, Habib Bourguiba University Hospital, Medenine, Tunisia Background & objectives: Seminal vesicle (SV) is an uncommon primary site for neoplasic-disease. The mixed epithelial and stromal tumour (MEST) of SV is extremely rare. Only a few cases have been reported. Here we report a case of a seminal vesicle MEST. Methods: N/A Results: A 38-year-old male, consulted for lower urinary-tract symp- toms. On physical examination, he had a palpable prostate at digital rectal exam. Abdominal and pelvic MRI reported a huge heterogeneous mass of the SV. The patient carried on a surgical resection. Macro- scopically, the mass measured 15cm in largest dimension, containing multi-locular cysts, including gelatinous substance. The histological examination revealed two distinctive components. The glandular one is lined by cubo-columnar cells, with focal nuclear pseudo-stratification without atypia. The stromal component is myxoid and paucicellular. The diagnosis of MEST was then made. The patient’s postoperative recovery was uneventful, he was alive and without evidence of diseases recurrence 4 months after the surgery. Conclusion: MEST of seminal vesicle is a rare entity. Patient’s long- term-follow-up with radiological exploration is recommended after tumour removal to control the possibility of recurrence. These neo- plasms have been described under various names such as cystadenoma, but the distinction between them remains a subject of debate, that is why more histological details are needed to better characterize and study them in the future. E-PS-24-028 Assessment of the prognostic role of PDL-1 in prostate cancer ver- sus benign prostate hyperplasia C. Ionescu*, M. Aschie, G.C. Cozaru, A. Mitroi, G.I. Baltatescu, A.A. Nicolau, N. Dobrin, S. Topliceanu, M. Enciu *CEDMOG “Ovidius” University of Constanta / “Sf. Apostol Andrei” Emergency County Hospital of Constanta, Romania Background & objectives: PD-L1 is a type-I transmembrane glyco- protein which correlates with a poor prognosis. Therefore, we aimed to determine the expression of PDL-1 in biopsies of human prostate