ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 PS-05-002 Uveal melanoma: ten years of experience and behaviour in the Principality of Asturias. A retrospective analysis M. Berríos-Hernández*, M.d.l.P. González-Gutiérrez, H.E. Tor- res-Rivas, N. González-Ortega, L.M. Fernández Fernández, C. Fuente-Díaz, M. García-Martínez, V. Blanco-Lorenzo, B. Vivanco- Allende, C. González del Rey-Rodríguez, A. Encinas-Muñiz *Hospital Universitario Central de Asturias, Spain Background & objectives: Uveal melanoma (UM) is the most common primary intraocular neoplasm in adults, arising from mel- anocytes located in the iris (4%), ciliary body (6%), or choroid (90%). It represents 2 cases per million per year in Spain and Italy (Southern Europe). Methods: We performed a descriptive and retrospective analysis for ten years (2011-2021) on patients diagnosed of UM from dif- ferent public medical institutions from the Health Service of the Principality of Asturias (SESPA). The information was obtained through the Hospital Registry of Tumours in Asturias. Results: Twenty-five patients were included in this study with a median age of 62-year-old. Predominant histologic subtype was epithelioid mela- noma (28%), followed by spindle cells (24%) and mixed (24%), subtype was not available in 6 patients (24%). Most of them presented as local stage (64%) and underwent radical surgery (88%). Most cases affected the choroid (80%) and a smaller group the ciliary body (20%). We found no cases with iris involvement. A small percentage (8%) required radio- therapy and immunotherapy respectively. Four patients died with a mean of 4,43 years after diagnostic, three of them with metastatic disease. The other patients are being followed-up at the referral hospital. Conclusion: In recent years, numerous advances have been made in genetics and behaviour of UM. However, despite these efforts, sur- vival has not been improved and once metastatic disease progresses, the prognosis is poor and therapeutic options are very limited. The heterogeneity of the molecular pathways involved in this pathol- ogy has hindered the development of a specific drug for advanced disease. Therefore, more studies are needed to achieve this. PS-05-003 Retinoblastoma in Ireland; the next generation sequencing molecular profiles of selected enucleation cases with a special focus on non-RB1 mutations and a comprehensive review of the retinoblastoma caseload in Ireland over the past 20 years J. Maguire*, A. Greene, M. Capra, L. Bradley, A. Green, C. Hartnett, S. Kennedy *St Vincent’s University Hospital, Ireland Background & objectives: Increasingly, retinoblastoma has been linked to somatic gene abnormalities beyond RB1, especially BCOR, a BCL-6 co-repressor gene. Our aim is to assess the molec- ular profile of selected retinoblastoma specimens and to review 20 years of retinoblastoma in the Irish population. Methods: Using the hospital database of the national ophthalmic centre, all enucleation specimens for suspected retinoblastoma performed in Ireland over the past 20 years (2001 – 2020) were analysed under various headings, including age at surgery, sex, lat- erality, diagnosis, and histopathological features including tumour differentiation, extent and stage. 6 selected cases were sent for somatic molecular analysis using next generation sequencing. Results: 65 enucleations were performed on 63 children. 61 speci- mens showed retinoblastoma. On average 3.2 surgeries were per- formed per year. 41% were female, 59% male. The average age at surgery was 2.72 years. 8% of the patients had undergone neo- adjuvant therapy prior to the enucleation procedure. 75% of the tumours were moderately to poorly differentiated, 61% had optic nerve invasion and 5% had a positive optic nerve margin. 5 of the cases referred for molecular profiling had a somatic RB1 variant. The remaining case, a 3 year old patient with a left sided, high grade, poorly differentiated retinoblastoma was found to have a mutation in BCOR, with no associated RB1 mutation. Conclusion: Our review shows that the rate of performance of enu- cleations for retinoblastoma in the Irish population over the past 20 years has remained stable. We identified a non-RB1 BCOR mutated retinoblastoma, associated with a high pathological grade. This supports the literature in highlighting BCOR as the most common non-RB1 gene to be mutated in retinoblastoma, and the importance of molecular profiling to identify non-RB1 somatic mutations and potentially higher grade, more aggressive tumour types to improve patient treatment. PS-05-004 Histopathologic findings of lens capsule and persistent hyper- plastic primary vitreous of Korean juvenile cataract patients Y.M. Kim*, C. Cho, J.Y. Kim, W.K. Kim, H.W. Kim, Y. Chun, W.S. Kim *Haeundae Paik Hospital, Republic of Korea Background & objectives: Persistent hyperplastic primary vitre- ous (PHPV) is a rare congenital anomaly in which the regression of the hyaloid vessel fails and primary vitreous persists after birth. The purpose of study was to determine the histologic features of congenital cataract and PHPV. Methods: Histopathologic examination of a total of 142 lens cap- sules from a retrospective cohort study of 106 consecutive unilat- eral and bilateral Korean juvenile cataract patients was conducted. Retrolenticular membranes of the 12 PHPV patients were reviewed for histology and immunohistochemistry with antibodies of CD31, CD34, Von Willebrand factor, Cytokeratin, Vimentin and TGF-β1 were performed. Results: 1) The frequency of PHPV in unilateral and bilateral Korean juvenile cataract patients was 11.3% (12/106). 2) Characteristic histologic features of PHPV, hypercellular membrane tissue consisting of either vascular structures and/or mesenchymal cells, were found in 75% (9/12) of cases at an age younger than 123 months. However, the hyaloid arteries and endothelium-lined blood vessels in the retrolenticular membranes were found only in 3 cases. 3) Six cases, including one case of bilateral PHPV, showed only mesenchymal cells. Three cases of clinically diagnosed PHPV did not show fibrovascular membranes by histology. 4) Endothelial cells of the vessels but not mesenchymal cells expressed TGF-β1 by immunohistochemistry. Conclusion: 1) Not all cases of PHPV have vascular structures in the retrolenticular membrane tissues. 2) Mesenchymal cells with or without vascular structures are found in most of cases (80%), which suggests that the vascular mesenchymal transformation could be one of the possible mechanisms in the process of vascular regres- sion of PHPV. 3) Mesenchymal transition of remnant foetal vas- cular structures in PHPV is independent of the patient’s age at the time of operation, or the size of retrolenticular membranes. Funding: This work was supported by a grant from Research year of Inje University in 20150684. PS-06 | Poster Session Paediatric and Perinatal Pathology PS-06-001 Paediatric soft tissue malignant tumours: a 16 year experience with literature review A. Bchir, N. Abdessayed*, T. Tlili, Y. Fejji, B. Sriha, M. Mokni S88