ECP 2023 Abstracts

S347 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Conclusion: In conclusion our results suggest that the local microenvi- ronment (IL-8, IL-6) modulate the dual behaviour of TNF-α in GOLD. A high concentration of IL-8 and IL-6 uncorrelated with TNF-α is an aggravating factor in COPD. E-PS-21-036 Feasibility and utility of transbronchial cryobiopsy in lung cancer V. Pasini*, S. Tomassetti, C.E. Comin *Università degli Studi di Firenze, Italy Background & objectives: Transbronchial lung cryobiopsy (TBLC) is an innovative procedure. Currently there are few data regarding its use in neoplastic lung disease, especially in mediastinal lymph node stag- ing. We evaluated the usefulness of TBLC for lung cancer diagnosis and predictive biomarkers analysis. Methods: Thirty-seven patients with lung and mediastinal lesions were included. Forty-two tumour specimens obtained by TBLC were com- pared to those obtained by other techniques, in particular EBUS-TBNA (7 cases) and trans-bronchial lung biopsy (TBLB, 10 cases). All speci- mens were formalin-fixed, paraffin-embedded, and hematoxylin-eosin stained. Samples included 33 peripheral lesions, 7 central lesions and 2 mediastinal lymph nodes. Results: Lung parenchyma was well preserved in all TBLC samples. TBLC was found to be diagnostic in 33 (78.5%) cases; TBLB was diagnostic in 4 (40%) cases; clot-core samples from EBUS-TBNA were diagnostic in 4 (57%) cases. The case cohort included 13 adenocar- cinomas, 8 squamous cell carcinomas, 3 small cell lung cancers, 4 Langerhans cell histiocytosis, 1 undifferentiated carcinoma, 1 myoepi- thelioma, 1 sclerosing pneumocytoma and 2 secondary tumours. The success rate of TBLC for PD-L1 evaluation was 100%. The success rate of TBLC specimens for DNA and RNA next-generation sequenc- ing (NGS) was 93.3%. Conclusion: Few studies have analysed the utility of this procedure in lung cancer. Our study demonstrated that TBLC might be a feasible approach for diagnosis and staging of lung cancer. Compared to EBUS- TBNA and TBLB, TBLC seems to provide more adequate samples for diagnosis and molecular analysis. Since tissue quality and quantity are still the most important issues in the therapeutic management of patients with lung cancer, we suggest that TBLC could represent a feasible alternative procedure in clinically selected cases. E-PS-21-037 Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH); a case report and review of the literature D. Proca*, M. Hussain, M. Jabbar, M. Mollaee, D. Zenezan *Temple University Health System, USA Background & objectives: Diffuse idiopathic pulmonary neuroendo- crine cell hyperplasia (DIPNECH) is a rare, under-diagnosed pulmo- nary benign disorder with numerous lesions that can progress to malig- nancy in 10% of cases. Histologically, it manifests as a proliferation of bland neuroendocrine (NE) cells around bronchial walls. Methods: We report a case of DIPNECH that was incidentally diag- nosed in an explanted lung from a 65 yo female with end stage lung disease due to COPD. Her clinical history includes a 40- pack year smoking history. Imaging before the transplant showed mild narrowing of the bronchi in the expiratory phase, focal thickening of bronchial walls and severe emphysema. Results: The explanted lung weighed 496 g and measured 20.5 x 10.0 x 1.2 cm. Sections revealed severe emphysema with subpleural bullae and anthracosis. Histologically, more than 10 aggregates and micronodules of NE cells were seen in all three lobes of the explanted right lung; the clus- ters measured up to 1.5 mm in greatest dimension and didn’t infiltrate through the basement membrane of the airways. The aggregates reacted positive with AE1/AE3, Chromogranin and Synaptophysin. Given the widespread nature of NE proliferation, a diagnosis of DIP- NECH was made after correlation with radiological studies. The chal- lenge in this case was the rarity of the diagnosis and nonspecific symp- toms overlapping with those of COPD. Conclusion: Our case is unique because the diagnosis was made in an explanted lung with end stage COPD. The definitive diagnosis is based on histopathologic examination, correlated with radiologic confirma- tion of the widespread nature of the lesions. Increased awareness of this preneoplastic disease is important due to its late diagnosis and its pro- pensity to evolve to invasive neuroendocrine tumours. The importance of this diagnosis is that the patient has to be followed up for progression of DIPNECH in the contralateral lung. E-PS-21-038 Endobronchial case of Langerhans cell histiocytosis (eosinophylic granuloma) E. Psychogiou*, P. Tziakou, P. Megas, M. Miliou, K. Papadopou- lou, A. Konstantinidou, E. Papadopoulou, D. Riga, C. Glava, I. Vamvakaris *General Hospital of Athens Sotiria, Greece Background & objectives: Eosinophilic granuloma is a form of Langerhans cell histiocytosis that can involve lung and bone. It is pri- marily an interstitial disease, although epithelial destruction may lead to alveolar involvement, characterized by an abnormal proliferation of histiocytes mixed with inflammatory cells. Methods: A 45-year-old man with free medical history was admitted to our hospital complaining of irritant cough. Fibreoptic bronchoscopy discovered a well-circumscribed polypoid mass, measuring 0,5 cm, protruding into trachea and biopsy was performed. Results: Histopathological sections revealed a polypoid lesion cov- ered with stratified squamous epithelium with subepithelial presence of lymphocytes, eosinophils, fibroblasts, histiocytes and larger cells with prominent nucleus and cytoplasmic groove. The immunohistochemi- cal analysis showed positivity to SMA, S-100, CD68, LCA, CD1a and Langerin while the stains Chromogranine, KLMW, p40, CD56 and CK19 were negative. Both histological findings and immunohisto- chemical results concluded to Langerhans’ cell histiocytosis. Conclusion: Pulmonary histiocytosis X is a form of Langerhans’ cell histiocytosis and it is characterized by an abnormal proliferation of Langerhans’ cells, which seem to serve as accessory cells for a lung immuno-pathologic response. It is observed exclusively in smokers. Histopathologic confirmation remains the most definitive way to estab- lish the precise diagnosis. The clinical course is uncertain and varies from complete or partial regression to progression until the end-stage lung. Treatment consists of corticosteroids, but cessation of smoking should be encouraged. E-PS-21-039 Pulmonary sclerosing pneumocytoma mimicking neuroendocrine tumour E. Psychogiou*, P. Tziakou, P. Megas, M. Miliou, K. Papadopoulou, A. Konstantinidou, E. Papadopoulou, D. Riga, C. Glava, I. Vamvakaris *General Hospital of Athens Sotiria, Greece Background & objectives: Sclerosing pneumocytoma is a rare benign pulmonary tumour composed of a dual population of surface cells resembling type II pneumocytes and round cells. It is typically soli- tary and peripheral and the patients are asymptomatic, with the tumour often discovered incidentally. Methods: A 39-year-old woman was admitted to our hospital after MSCT scan demonstrated a 2,3X1,4cm solid mass on her left lower