ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Conclusion: Histologically, differential diagnosis can be extremely challenging on small needle biopsy or frozen procedure. Especially, if biopsy is not satisfactory, PPHL can mimic infectious or inflam- matory disease (tuberculosis, granulomatous inflammation, etc.) as well as other pulmonary malignancy (adenocarcinoma). This study and literature review can be helpful for pathologists to diagnose PPHL properly. PS-16-002 Five-year experience of evaluation of PD-L1 expression on advanced non-small cell lung carcinoma – single centre study J. Stojsic* *University Clinical Centre Serbia, Serbia Background & objectives: About 80% of all diagnosed lung carci- noma is of non-small cell lung carcinoma (NSCLC) histological type. The aim was to evaluate results of PD-L1 expression on advanced non- small cell lung carcinoma (NSCLC) in five-year period. Methods: The percentage of expression PD-L1 (clone 22C3) in malignant cells was correlated on small and surgical samples according to the following parameters: age, gender, histological subtypes of NSCLC, stromal immunological/inflammatory cells and adequacy of samples. PD-L1 testing on demand and its expres- sion was divided into three groups: low, middle and high. Results: PD-L1 expression was evaluated in 802 patients, 2/3 of them were male and the most frequent in age 61-70, 64% ADC, 20% SCC and 13.3%-NOS. Low PD-L1 expression was found in 53%, weak in 19% and high in 28% NSCLC. Inflammatory/ immunological cells were registered in 45% of samples with high PD-L1 expression. Weak and moderate PD-L1 expression among genders was similar, without significance (p=0.689). Weak and high PD-L1 expression among aged groups was similar (p=0.645). PD-L1 expression according to histological subtypes of NSCLC was not significant (p=0.455). Low PD-L1 expression was found in inadequate samples (p<0.001). Inflammatory/immunological cells with PD-L1 expression were significantly higher in patients with higher expression (p<0.001). Conclusion: High PD-L1 expression was found in 28% NSCLC without correlation with histological subtype, gender and age of patients. High PD-L1 expression was associated with PD-L1 expression in stromal immunological cells. Presented results was similar with published ones in relevant literature. PS-16-003 Role of microRNAs miR-193b, miR-7, miR-25 and miR-301a as potential diagnostic marker in non small cell lung cancer (NSCLC) N. Krishnani*, N. Kumari, H. Baranwal, S. Singh, A. Nath *Sanjay Gandhi Post Graduate, Institute of Medical Sciences, India Background & objectives: NSCLC is leading cause of cancer-related death world over. MicroRNAs are emerging as potential non-invasive biomarker for early detection. We studied the role of circulating micro- RNAs miR-193b, miR-301a, miR-7 and miR-25 as non-invasive bio- marker in NSCLC in Indian population. Methods: Plasma samples from histology proven 101 NSCLC cases and 28 non-neoplastic controls including 18 chronic obstruc- tive pulmonary disease and 10 healthy individuals were tested for expression of microRNAs miR-193b, miR-7, miR-25 and miR-301a by real time PCR. Dysregulated microRNAs were correlated with clinicopathological features. Results: miR-193b (p=0.034) and miR-7 (p=0.4) were upregulated while miR-25 (p=0.2) and miR-301a (p=0.5) were downregulated in NSCLC compared to controls. The AUC was 0.636 (95% CI, 0.522-0.750; p =0.03). There was no significant association of microRNA dysregulation with age, gender, smoking, alcoholism, tuberculosis, lymph node status, pleural effusion and disease stage. miR-25 downregulation correlated with adenocarcinoma histology (p=0.03). miR-193b downregulation significantly correlated with survival (14.9 ± 1.5 months (p=0.03). Disease progression was seen in 12 patients in upregulated and in 3 patients in downregu- lated group with progression free survival of 9.7 ±1.1 months in upregulated 12.3 ±0.5 months in downregulated group (p value =0.04). Conclusion: miR-193b was significantly upregulated while miR- 25 and miR-301 were downregulated in NSCLC but were statisti- cally non-significant. These may act as pointers towards NSCLC diagnosis and suggest diligent search of malignancy in these patients. However, microRNA profiling and validation studies are required to develop microRNAs as a diagnostic tool. PS-16-004 Alveolar adenoma - clinicopathological characteristics of four cases A. Lovrenski*, N. Gardic, D. Tegeltija, T. Lakić *Faculty of Medicine, University of Novi Sad, Serbia Background & objectives: Alveolar adenoma is a rare, benign tumour of the lung which have broad spectrum of differential diagnosis. In order to minimize the possibility of errors in the diagnosis of simi- lar lung lesions, pathohistological finding should be completed with immunohistochemistry. Methods: Retrospective study included 4 cases of lung alveolar adenoma, diagnosed between 2010 and 2020. All patients were treated surgically, in one case with video-assisted thoracoscopy, while in others a thoracotomy was performed. The type of resection performed was wedge resection and lobectomy (3:1). In all cases, the tumour was located in the lower lobes. Results: Frozen section findings in all cases were classified as benign lesions. On FFPE sections, tumours showed characteristic multicystic morphology with cystic structures lined with regular pneumocytes separated by septa, built of spindle cells with lymphocyte infil- trates. Granular eosinophilic detritus was found in the cysts lumens. Tumours were relatively clearly demarcated from surrounding paren- chyma, without capsule and with expansive growth compressing the lung parenchyma. Immunohistochemical analysis in all cases showed immunoreactivity of epithelial component to TTF-1, panCK, EMA, while the immunomarkers D2-40, HMB45, MelanA and S-100 were negative. The stromal component was Vimentin positive in all cases, while in one case in addition to vimentin, SMA and CD34 were posi- tive too. Conclusion: The features of alveolar adenoma may mimic other types of lung tumours, consequently leading to difficulties in the differential diagnosis. Thus, accurate diagnosis of alveolar ade- noma is based on a combination of pathological and immunohis- tochemical findings. PS-16-005 Is imprint cytology an efficient alternative to traditional frozen section in intraoperative diagnosis of lung adenocarcinoma? A. Lovrenski*, N. Gardic, D. Tegeltija *Faculty of Medicine, University of Novi Sad, Serbia S150