ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 PS-23-007 Clinicopathological characterisation and molecular profiling of H3 G34-mutant high-grade gliomas in paediatric and young adult patients Z. Reisz*, J.P. Lavrador, N. Sibtain, K. Rajvani, R. Bhangoo, C. Bleil, B. Zebian, K. Ashkan, S. Nevis, L. Bhaw, R. Laxton, A. Afshari-Mehr, A. King, I. Bodi, S. Al-Sarraj *Clinical Neuropathology, King’s College Hospital, United Kingdom Background & objectives: Diffuse hemispheric glioma, H3 G34- mutant is a novel paediatric tumour type in the fifth edition of the WHO Classification of CNS Tumours. We present here a global review of a departmental case series to provide further clarification on this entity. Methods: Retrospective departmental analysis of 931 paediatric/young adult neuroepithelial tumours identified eleven cases harbouring H3 G34R/Vmutation. Clinicopathological and molecular data were reviewed. Results: H3 G34R/V mutation was a rare molecular event among CNS tumours (1.2%; median age: 17.3 years). MRI revealed features of high-grade gliomas often involving multiple lobes and deep structures that precluded gross total resection. Histologically, the tumours showed marked heterogeneity and aggressive spreading along pre-existing brain structures and leptomeninges. Besides diagnostic H3 G34R/V mutation, most cases harboured pathogenic variants in TP53 and ATRX genes. Potential targetable mutations in PDGFRA and PIK3CA genes were detected in 5 cases. Methylation profiling was a useful diagnostic tool and it also highlighted common structural chromosome abnormalities including PDGFRA amplification, CDKN2A/B deletion and various CNVs in cyclinD-CDK4/6-Rb pathway. The mean overall survival was 19.1 months. Conclusion: H3 G34-mutant diffuse hemispheric glioma is a dis- tinct CNS tumour type sharing common radiological and patho- logical features and associated with a dismal prognosis. Genomic landscaping of individual tumours might give an opportunity to tailoring individualised therapies and improve patient management. PS-23-008 The role of AKT in prognosis of breast cancer brain metastases J. Gama*, R. Oliveira, C. Abrantes, P. Teixeira, F. Silva, P. Figue- iredo, O. Rebelo, M.A. Cipriano *Centro Hospitalar e Universitário, Portugal Background & objectives: Brain metastases in breast cancer are linked to a poor prognosis and are a common event. Immunohistochemistry assessment of biomarkers may predict prognosis and guide therapy. Our goal was to investigate the role of the PTEN/AKT/PI3K pathway and androgen receptors. Methods: A retrospective transversal study of 114 patients (diag- nosed between 2000-2016) with breast cancer brain metastases was carried out using archival biological material. Expression of PTEN, AKT, PI3K and Androgen receptors was assessed by immunohistochemistry. Clinical and pathological data were retrieved from the hospital database. The local ethical committee approved this study. Results: After a mean of 20.3±29.5 months, the median overall survival was of 10 months. The overexpression of AKT was associated with a worse overall survival on univariate analysis (7 months (1.3-12.8) vs 12 months (5.6-18.2), p=0.034), but this finding was not confirmed in multi- variate analysis (p=0.090). No difference in overall survival was seen associated with the expression of PTEN (p=0.608), PI3K (p=0.167) and androgen receptors (p=0.894) Conclusion: AKT is usually linked to tumour progression and drug resistance, thus it is expected that AKT overexpression is linked to worse overall survival in breast cancer and may have prognostic impact on survival in patients BCBM. Modulation of AKT and its pathway may be a strategy for guiding stratification and therapy of patients. PS-23-009 Choroid plexus tumours: clinicopathological analysis of 10 cases M. Alaya*, A. Zehani, B. Chelly, A. Ayari, H. Azouz, I. Chelly, K. Bellil, S. Haouet *Department of Pathology, La Rabta Hospital, Tunis, Tunisia Background & objectives: Choroid plexus tumours are rare intraven- tricular neoplasms arising from choroid plexus epithelium. 3 histologi- cal types have been described by the WHO : Papilloma, Atypical papil- loma and Carcinoma. This study aims to highlight the epidemiological and pathological characteristics of this entity. Methods: Our study is retrospective about ten cases of choroid plexus tumours collected in the pathology department of La Rabta hospital over a period of 22 years from 2000 to 2022. The data on patients’ gender, age, pathomorphological characteristics and location of the tumour, clinical presentation and operative details were retrieved from the National Institute of Neurology of Tunis. Results: 10 cases were evaluable. They were 6female and 4male patients, ages ranging from 5 to 50 years with an average of 16,3 years. The clinical presentation was dominated by intracranial pres- sure syndrome. The main diagnostic tool was CT-scan and most patients with supratentorial tumour were children. All patients underwent surgical treatment. The histological examination has revealed 6 cases of papillomas and 4 cases of carcinomas. The papillomas corresponded to papillary tumoral proliferations with very low mitotic activity and whose cells were cuboid, resembling those of the normal choroid plexus. Carcinomas, on the other hand, appeared as frankly malignant tumours with significant mitotic activity, less good differentiation and areas of necrosis. Conclusion: Choroid plexus tumours remain a very rare entity affecting mainly children and are classified into 3 histological types. Higher frequency and better prognosis have been seen with choroid plexus-papillomas. Surgery remains the mainstay of treat- ment, often followed by adjuvant treatment in case of choroid plexus-carcinomas. PS-23-010 Hydatid cysts of the nervous cerebral system, an unusual loca- tion: about 9 cases M. Alaya*, H. Azouz, A. Ayari, B. Chelly, A. Zehani, I. Chelly, K. Bellil, S. Haouet *Department of Pathology, La Rabta Hospital, Tunis, Tunisia Background & objectives: Hydatid cyst is a parasitic tapeworm dis- ease caused by the larval stage of Echinococcus Granulosus usually reported in the liver. The NCS is still a rare location. Our aim is to define the epidemiological and pathological characteristics of this entity. Methods: Our study is retrospective about nine cases of hydatid cysts of the nervous central system (NCS) collected in the pathol- ogy department of La Rabta hospital over a period of 6 years from 2016 to 2022. The data on patients’ gender, age, histology and location of the cyst and operative details were retrieved from the National Institute of Neurology of Tunis. S163