ECP 2023 Abstracts

S120 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Background & objectives: Pulmonary amyloidosis is rare and can involve the tracheobronchial tree, lung and pleural parenchyma. Amy- loid subtype analysis is important for patient management. An audit was performed to evaluate detection and pathological management of these cases over a 14-year period. Methods: A COGNOS database search was performed at the Pathol- ogy Department, CUH from 2008-2022 for diagnosed airway and lung parenchymal amyloid. Data evaluated included number of cases, age, gender, localization of deposits (confirmed by Congo Red), disease association, and amyloid sub-type performed at the National Amy- loidosis Centre, UK. Amyloid that did not stain with an antibody was termed non-AA amyloid. Results: 15 patients identified by Congo Red stain from 2489 speci- mens (0.6%) - 12 male, 3 female patients, mean age 72 (range 51-89 years). Of 12 cases sub-typed, Amyloid light chain (AL), Lambda sub- type was the most common. Tracheobronchial (n=5): 3 AL amyloid sub-type, unassociated with a clonal plasma cell proliferation. 2 non-AA amyloid, one associated with an adenocarcinoma. Lung parenchyma (n=8): 6 cases sub-typed, 4 AL amyloid sub-type with a nodular distribution pattern, one associated with a plasmacytoma, and one with a squamous cell carcinoma. Two were non-AA amyloid sub-type with an interstitial pattern, one with a known myeloma history. Pleura (n=2): BothAL amyloid sub-type and previous amyloidosis diagnoses. Conclusion: Pulmonary amyloidosis can be either localized or sys- temic and usually presents in one of three different forms – nodular, diffuse alveolar-septal, or tracheobronchial amyloidosis. AL Lambda subtype, unassociated with a systemic clonal plasma cell prolifera- tion, was the dominant subtype similar to current literature. Amyloid subtyping guided management for all of these patients and continues to be standard practise within our laboratory. PS-20-006 Histological analysis of lung grafts lesions related to cold preservation at 10C J. Martin Lopez*, P. Gil Bernabé, S. Martin Poza, S. Crowley, G. Silvestre Egea, R. Laporta, C. Salas Anton, J.L. Campo Cañaveral *Department of Pathology. Hospital U. Puerta de Hierro, Spain Background & objectives: Cold preservation of the lung graft at 10°C seems a promising method to safely extend the cold ischemia time. We analysed the impact of preservation at 10 °C compared to standard preservation at 4 °C in lung transplants. Methods: This is a prospective single-arm study of lung transplants (LTx) performed between September 2021 and September 2022. Those with doubts in perfusion and preservation processes, or those subsidiaries of ex vivo assessment were excluded. Biopsies of the lung grafts were taken at different times during the transplant. The presence of neutro- phils, alveolar edema and interstitial infiltrate were evaluated and graded. Results: 41 patients were included (n=20 preserved at 10°C; n=21 at 4°C). There were no differences regarding demographic variables and the indication for transplantation. Total preservation times were statisti- cally longer (p<0.001) in the 10°C group [1st lung; 662 min (R 428- 807); second lung; 813 (R 620-946)] than in the 4°C group [1st lung; 360 min (R 320-400); second lung; 439 (R 395-490)]. Histologically, no relevant inflammatory or exudative changes were recognized that would make it possible to identify the preservation method chosen. Some sam- ples had intravascular thrombi and scaly changes that will be analysed in a second phase. Mortality at 30 and 90 days was 0% in both groups. Conclusion: Our study proposes the evaluation of inflammatory medi- ators and the histological assessment of acute lung injury to study whether preservation methods affect donor lungs. Only a few series have evaluated this previously. We show that preservation at 10°C seems to be a safe and feasible strategy to intentionally prolong cold ischemia time in lung grafts, rendering it advantageous in the logistics of a lung transplant program so it could, in the future, be considered a semi-scheduled procedure. PS-20-007 Do more and increasing of diagnostic yield with rapid on-site evalu- ation ROSE in trans-thoracic needle aspiration/biopsy TTNA/B S. Melotti*, A. Velotti Fino, C. Ricci, N. Nannini, A. De Leo, M. Sirolli, E. Mengozzi, D. Papadopoulos, A. Bruno, M. Fiorentino, F. Ambrosi *Pathology Unit, Maggiore Hospital-AUSL Bologna, Bologna, Italy, School of Anatomic Pathology, Department of Biomedical and Neu- romotor Sciences, University of Bologna, Italy Background & objectives: ROSE is a cytological technique that supports sample evaluation during endobronchial procedures. We aim to uncover the extent to which ROSE of TTNA/B samples under CT and US-guided can safely and cost-effectively reduce the necessity for additional procedures. Methods: Two groups of patients who underwent TTNA/B for thoracic lesions (89% from the lung and 11% from mediastinum) have been compared. The first group-cohort A not supported by ROSE, as well as the latter (cohort B) was supported by a systematic ROSE during the radiological procedures. All data have been retrieved from the digital archives of the Department of Pathology. Results: 91.04% of cohort A patients’ preliminary diagnosis has been rendered during CT or US-guided procedures supported by ROSE, and in 68.7% of cases only a single TTNB pass was sufficient for the diag- nosis, the immunohistochemical and the molecular characterization. Furthermore, the number of inadequate procedures reduced from 29.90% in cohort A in contrast to 8.96% in cohort B (<0.005 Fisher exact). Due to an average improvement in the samples quality, an NGS charac- terization was carried out in 60% cases in cohort B, as opposed to 45% of cohort A. The PD-L1 immunohistochemistry has been evaluated in 69.04% of non-small cell lung cancer in cohort B versus 25% of cohort A. Conclusion: Performing ROSE during TTNA/B consistently reduced the number of inadequate samples and increased diagnostic yield. It also allowed the collection in one single procedure of sufficient tissue for further molecular and immunohistochemical diagnostic analysis. PS-20-008 Wnt3α in a mouse model of bleomycin induced lung fibrosis A. Ognjenović*, S. Čužić, M. Antolić, V. Milutinović, Ž. Anzulović Šanta, B. Hrvačić, I. Glojnarić *Selvita Ltd., Croatia Background & objectives: Wnt signalling pathway plays important role in lung development, regeneration, and disease progression. Aim of the study was to identify cells that are the source of Wnt3α, a member of the canonical Wnt pathway, in naïve and fibrotic murine lungs. Methods: C57BL/6N mice were divided into naïve control and bleo- mycin-challenged group. Lung tissue was sampled on days 7, 9, 14 and 21 following intranasal bleomycin challenge. Formalin-fixed paraffin- embedded lung tissue sections were stained by double immunofluores- cence (CC10/Wnt3α and CD206/Wnt3α). Slides were scanned using AxioScan.Z1 scanner (Zeiss). Quantification of CC10/Wnt3α positive surface within bronchi surface was performed using Visiopharm software. Results: The main source of Wnt3α in naïve mice lungs was the bronchial epithelium. In bronchial epithelium, most of the club cells (CC10-positive cells) expressed Wnt3α; approximately 80% of the cells. Bleomycin chal- lenge induced club cell damage and depletion. Despite the subsequent recovery of the club cell population by day 21 post-bleomycin challenge, less than 40% of the club cells expressed Wnt3α. At the same time, Wnt3α became expressed within the areas of pathological bronchioliza- tion (CC10-positive cells). On day 21 post-bleomycin Wnt3α was present within a small portion of M2 macrophages (CD206-positive cells).