ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 various medical displays and quantify their impact on the visual repro- ducibility of significant clinical structures. Methods: Using display simulation models, we quantify the impact of modern medical displays on the visualization of whole slide images (WSIs). We included H&E and IHC-stained slides from 400 patients, originating from different laboratories which were digitized with scanners from various vendors. In addition to overall statistics, the perceptual contrast for certain histological structures is measured and compared for various displays. Results: Using the ΔE method, we found that different displays may introduce a significant difference in perceptual contrast of certain histological structures by up to 2.7ΔE. This effect can further deteriorate over time, due to a decrease in display luminance. This observation advocates the need for continuous display calibration and adequate quality assurance mechanisms. Some medical grade displays for pathology incorporate such quality assurance automatically by factoring in the ambient light- ing conditions and optimizing visibility of subtle colour differ- ences. This can increase the contrast of histological features such as nuclei characteristics by at least additional 0.9 ΔE. Conclusion: In radiology, display systems have been exten- sively studied, resulting in standardization, clear requirements, and guidelines. However, image data, viewing modalities and ambient conditions in digital pathology differ greatly from radi- ology. Therefore, independent investigations must be conducted here. The presented experiments illustrate the variability between displays and the perceived image characteristics for specific his- tological features in order to translate generic display specifica- tions into clinical implications. PS-25 | Poster Session Pathology in Favour of Developing Countries PS-25-001 Postmortem ultrasound estimation of foetal gestational age by transcerebellar diameter and cerebellar vermis height N. Rakislova*, L. Garcia-Otero, G. Arca, L. Marimon, R. Gonza- lez, F.M. Pérez, N. Carreras-Dieguez, J. Ordi, C. Menéndez *Hospital Clínic Barcelona, Spain Background & objectives: Adequate data on gestational age at perina- tal autopsy is usually non available in many low-income countries. We aimed to evaluate the usefulness of post-mortem ultrasound measure- ment of trans-cerebellar diameter and height of cerebellar vermis for gestational age determination. Methods: Gestational age, intrauterine growth parameters and ultrasound reports were retrieved for all consecutive perinatal autopsy cases from July 2020 to April 2022. A total of 70 cases (68 stillbirths and 2 neonates) with no intrauterine growth restriction or ultrasound brain abnormalities were enrolled. All measurements were performed through the anterior fontanelle. The Pearson cor- relation coefficient (r) and p-values were calculated. Results: Mean (SD) gestational age was 22.7 weeks (4.5). Most of stillborn deaths (54; 80%) were due to legal abortion. Other intrauterine deaths (14; 20%) comprised chorioamnionitis (42%), intrauterine hypoxia (42%) and unknown causes (16%). The two neonatal deaths were due to prematurity complications. Trans-cer- ebellar diameter was measured in all 70 cases (100%) and height of cerebellar vermis in 60/70 cases (85.7%). Trans-cerebellar diameter ranged from 18.5 mm at 17.5 weeks to 56.2 at 40.6 weeks. Height of cerebellar vermis ranged from 8 mm (at 17.5 weeks) to 30.6 at 40.6 weeks. Both trans-cerebellar diameter and height of cerebel- lar vermis correlated significantly with gestational age (r=0.84; p<0.0001 and r=0.87; p<0.0001, respectively). Conclusion: Post-mortem ultrasound measurements of trans-cer- ebellar diameter and height of cerebellar vermis could be useful in low-resource settings for obtaining gestational age data. Both measurements can be rapidly conducted with portable ultrasound device. These data are especially useful when evaluating results of minimally invasive tissue sampling (MITS), a procedure based on core needle biopsies, which use is currently expanding in countries of Sub-Saharan Africa and South-East Asia. Funding: These results are part of the project "Anthropometric parameters and biomarkers for identification of prematurity and pre-eclampsia as causes of perinatal mortality" managed by Bar- celona Institute for Global Health (ISGlobal) and funded by Bill & Melinda Gates Foundation (OPP1196642) PS-26 | Poster Session Uropathology PS-26-001 The morphological spectrum and molecular features of somatic malignant transformation in germ cell tumours J. Lobo*, Â. Rodrigues, R. Henrique, A. Christiansen, J. Beyer, H. Moch, P.K. Bode *IPO Porto, Portugal Background & objectives: Somatic malignant transformation (SMT) arising in germ cell tumours (GCTs) is an infrequent, but clinically relevant event. There is only limited knowledge on the morphological spectrum of SMT, and therapeutic management of these patients is poorly defined. Methods: In this work we revisit two consecutive case series (n=756) of GCTs diagnosed at University Hospital Zurich, Swit- zerland and IPO Porto, Portugal. Clinicopathological data of SMT arising in GCT were determined, with focus on the histopathologi- cal spectrum, and molecular aspects were obtained by Fluorescence in situ Hybridization (FISH) and Next Generation Sequencing (NGS). Results: 30 male patients (28 testicular, 2 extragonadal) were included (representing 4% of GCT patients diagnosed in both institutes). The most common SMT were adenocarcinoma (n=8), embryonic-type neuroectodermal tumours (ENETs, n=8) and rhabdomyosarcoma (n=6), but a wide range of challenging mor- phologies were depicted, including low-grade neuroglial tumour, adenosquamous carcinoma, neuroblastoma and neuroendocrine car- cinoma. SMT was found in 15 primary tumours and in 27 metasta- ses of these 30 patients, the latter showing poorer overall-survival. Adenocarcinoma occurred in metastases post-chemotherapy, but not in the testis. 12p gains were identified in all cases. NGS results were available in 6 patients. Clinical trials/targeted treatments based on the molecular profile were recommended in 4 patients. Conclusion: SMT arising in GCTs represents a diagnostic chal- lenge and should be confirmed by a specialized uropathologist. NGS based treatment recommendations may improve outcome of these patients. Funding: JL is recipient of fellowships from FCT – Fundação para a Ciência e Tecnologia (PTDC/MEC-URO/ 29043/2017 and SFRH/ BD/132751/2017). JL would like to acknowledge the support of MSD (“Prémio de Investigação em Saúde”), Banco Carregosa / Secção Regional do Norte da Ordem dos Médicos (SRNOM) and Fundação Rui Osório de Castro / Millennium bcp. PS-26-002 Eosinophilic solid and cystic renal cell carcinoma and renal cell carcinomas with TFEB alterations: a comparative study S167