ECP 2023 Abstracts

S339 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 women. PSP occurs in the peripheral parenchyma of the lung and can affect any lobe. Clinically, most patients are asymptomatic. Rarely, non-specific respiratory symptoms can be seen. Methods: A 48-year-old female presented in our hospital, who had a lung solid nodular lesion incidentally found by a chest X-ray. Pet/CT scan resulted as "A well-circumscribed slightly hypermetabolic mass lesion of approximately 3x2.6cm in diameter located in the lower lobe of the right lung". Clinically thought of as lung cancer, the mass was excised and sent for histopathological examination. Results: We observed an infiltrative proliferation in replace of the lung parenchyma in microscopic examination. The proliferation consisted of two types of cells: cuboidal "surface cells" resembling type 2 pneu- mocytes and polygonal "round cells" with eosinophilic cytoplasm. We saw that surface cells lined papillary structures while round cells formed solid islands. Additionally, we noted a sclerotic stroma. An immunohistochemical panel consisting of markers was applied, and both cell types were positive for Epithelial Membrane Antigen(EMA) and Thyroid Transcription Factor-1(TTF-1). Napsin, AE1/3, and CK7 were positive in surface cells and negative in round cells. And 3% of tumour cells were positive for Ki67. No necrosis, frequent mitoses and marked pleomorphism were observed. Conclusion: The differential diagnosis of pulmonary sclerosing pneu- mocytoma includes benign lesions as well as malignant neoplasms such as primary carcinoma of the lung, metastatic carcinoma, carcinoid tumour. The different treatment options for these tumours emphasize the importance of making an accurate diagnosis. And since PSP can be confused radiologically and microscopically with a malignant neo- plasm, this case has been presented. E-PS-21-005 Extended SARS-CoV-2 pneumonia complicated by cytomegalovi- rus and aspergillus infection P. Babal*, L. Krivosikova, T. Kuracinova, P. Martanovic, P. Janega *Institute of Pathological Anatomy, Medical faculty of the Comenius University in Bratislava, Slovakia Background & objectives: Infection by SARS-CoV-2 affects predomi- nantly the respiratory system causing an acute disease in the majority of cases. Many patients develop lasting symptomatology of the long COVID. Methods: Clinical course: We report a patient with bronchial asthma who presented with initiating COVID pneumonia, was hospitalized and received oxygen therapy for two weeks. Successively, he developed interstitial lung fibrosis. Two months later the patient died with signs of rapid worsening dyspnea. Results: At autopsy, even after more than 2 months, the SARS-CoV-2 virus still could be detected with immunohistochemistry in scattered alveolar epithelial cells of lungs, although the tests from the nasophar- ynx were negative. In addition to that, there was diffuse distribution of alveolar epithelia with large nuclear inclusions immunohistochemi- cally positive for cytomegalovirus and multiple foci of necrosis with Aspergillus hyphae. Conclusion: Immune dysregulation induced by COVID-19 and cor- ticoid therapy administered to the patient created conditions favour- able for extended persistence of the SARS-CoV-2 infection in lungs complicated by fatal combination of cytomegalovirus and Aspergillus infection. Funding: BIOVID-19, ITMS: 313011AVG3, co-financed by the Euro- pean Regional Development Fund E-PS-21-007 Cross sectional study of metastases to the lung on 5,867 lung core biopsy specimens M. Bonert*, C. Finley, A. Naqvi *McMaster University / St. Joseph’s Healthcare Hamilton, Canada Background & objectives: Lung metastases are a common pulmonary pathology specimen. This work examines metastases/possible metasta- ses (MPM) through the lens of lung core specimens only. Prior work on the data set examined TTF1 negative lung adenocarcinomas (TNLA) and identified 50 specimens. Methods: All lung core biopsies cases accessioned 2011-2020 were retrieved from a regional centre. Specimens were classified by location, diagnosis, diagnostic category (benign/ suspicious/ malignant) with a hierarchical free text string-matching algorithm (HFTSMA) that was previously validated. The MPM assessment of the TNLA cases was evaluated. All MPM reports were reviewed by a pathologist. Results: The cohort had 5,867 specimens from 4,973 patients. 3,226/5,867 were malignant and 600/3,226 were MPM per HFTSMA. 19/50 TNLAs were identified as MPM by HFTSMA. 459/600 speci- mens were classified as MPM on pathologist report review. Primaries by frequency were colorectal cancer (CRC) 82, breast 42, melanoma 37, kidney 31, gynaecologic 26, soft tissue 21, prostate 19, gastrointes- tinal not CRC 17, urothelial 17, miscellaneous 14, unknown/possible metastasis (UPM) 153. The UPMs were subclassified in five hierarchi- cal groups: squamous cell carcinoma (33/153), CK7+/TTF-1 negative tumours (50/153), CK5+ tumours (8/153), CK20+ tumours (18/153), and unclassified (44/153). More lesions were on the right (235) than left (189); however, this was not statistically significant. Conclusion: The HFTSMA assisted categorization facilitated the analysis; however, it was not sufficiently accurate without pathologist review. The classification of the 50 TNLA cases suggests MPM cases are missing, and work remains. Approximately 4-5% of malignan- cies (153/3,226) were unclassified in relation to primary site. Clinical information is required to differentiate MPMs from primary tumours; however, this is most often not provided. Standardized history and pathologic reporting would be desirable and could facilitate work that provides further insight into the MPM-primary interface. E-PS-21-008 Primary salivary gland-type carcinomas of the respiratory tract: a case series review from an oncology institute A. Coutada*, J. Azevedo, N. Coimbra *Department of Pathology, Portuguese Oncology Institute of Porto / Porto Comprehensive Cancer Center Raquel Seruca, Portugal Background & objectives: Primary salivary gland-like carcinomas (PSGCs) of the respiratory tract are rare neoplasms that occur primarily in the central airways and apparently originate from the submucosal glands. Herein, we describe a single institution experience regarding this type of tumours. Methods: We conducted a retrospective analysis of all PSGCs of the respiratory tract diagnosed at our Institution between 1995 and 2022. Evaluation of clinicopathologic features, such as age at diagnosis, localization and number and local of metastases were assessed. Both biopsy and surgical specimen results, including histomorphology, tumour grade, immunohistochemistry and genetic results were also included. Results: In total we identified 14 cases: 9 mucoepidermoid carcino- mas (MECs) and 5 adenoid-cystic carcinomas (ACCs). Median age was lower in MECs (54.4 years vs 60.6 years), with male predomi- nance in MECs and female in ACCs. Lobectomy was the main surgical treatment. The majority of tumours were localized in central region. Most MECs were low-grade. Genetic analysis showed 2 MECs with MAML2 rearrangement and 1 ACC with MYB rearrangement. Follow- up (median, 39.4 months) revealed invasion of adjacent structures (2 ACCs), lymph node metastases (1 MEC) and local and distant metas- tases (2 MACs; 1 ACC). Median overall-survival was 43.9 months for MECs and 31.6 months for ACCs. Conclusion: Diagnosing PSGCs of the respiratory tract can be chal- lenging due to their rarity and diverse morphology. Molecular testing