ECP 2023 Abstracts

S338 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 medical institutes. In the questionnaire, the amount of histotechnical knowledge acquired during training period of residents was evaluated. The domains where our institutes failed to meet the international guide- lines were highlighted. Results: Majority of our institutes lacked the appropriate training of residents regarding routine and advanced histotechniques. The main factors being lack of any scheduled rotation on different stations, non- availability of ancillary testing in various institutes or lack of inter- est at the end of both supervisor and residents. In some institutes the technical staff itself wasn’t competent enough to provide effective training of histotechniques to the residents. Learning histotechniques in developing countries like ours is important due to the facts that histopathologists in different private and particularly in governmental institutions usually have the additional tasks of laboratory management, supervision of technical staff and monitoring various quality indicators in addition to routine reporting. Conclusion: It is vital for histopathology residents to learn the know how of basic core and advanced histotechniques performed in histo- pathology laboratory. Our study helped in highlighting a gap in the histopathology residency programs, running in majority of the private and governmental institutes of our country. The reasons behind this pitfall, identified in this study can be promising to uplift the training standards of histopathology residents and thus maintaining their good standard practices as future consultants and laboratory supervisors. E-PS-21 | E-Posters Pulmonary Pathology E-PS-21-001 Pulmonary adenofibroma: study of 10 cases of a rare lung lesion A. Álvarez-Muñoz*, J. Machuca-Aguado, E. Rodríguez-Zarco, S. Umbría-Jiménez, A. García-Escudero, M.A. Idoate Gastearena *Virgen Macarena University Hospital, Seville, Spain Background & objectives: Pulmonary adenofibroma (PA) is a rare lung tumour not included in the last the WHO classification of lung tumours. Ours is the second largest serie. This study aims to increase the knowledge of this entity describing clinicopathological and molecu- lar features. Methods: Retrospective observational clinicopathological study of a serie of 10 cases of pulmonary adenofibromas in the period 2002-2022. Clinicopathological features were described and immunohistochemical and molecular analysis was performed, evaluated by three independ- ent pathologists. Immunohistochemical techniques were performed using the following antibodies: CD34, STAT6, BCL2, CD99, TTF1, ER, PR, S100 and SMA. In addition, NATB2-STAT6 gene fusion was performed by FISH. Results: Patients ranged in age from 41 to 75 years (mean 60.1) and 70% were male. Most of the patients were diagnosed on routine imaging. The most frequent location was the right lower lobe (40%), (mean size 1.4 cm). No patient recurrence or death due to the lesion was observed. All the cases showed a biphasic histologic pattern with a glandular epithelial component and a stromal spindle cell component. In none of these components were evident histologic signs of malignancy. Immunohistochemistry showed diffuse stromal positivity in all cases for BCL2, 9 for CD34 and 6 for STAT6. Strong TTF1 staining was observed in the epithelial component in all cases. Conclusion: We report the clinicopathologic features of a new serie of PA, a rare neoplasm. The nature of this lesion has not been clarified: hamartomatous origin versus neoplastic stromal proliferation. In this sense, some studies report NATB2-STAT6 translocation in PA, similar to solitary fibrous tumour (SFT). The positive immunostaining for STAT6 and CD34 in most of our cases may suggest that at least some of the PA are indeed intrapulmonary SFT with an entrapped epithelial component. E-PS-21-002 Endobronchial lipoma, an extremely rare benign tumour involv- ing the lung R. Ayadi*, E. Braham, F. Loued, H. Ichrak, O. Ismail, A. Ayadi *Hôpital Abderrahmane Mami, Tunisia Background & objectives: Endobronchial lipomas are extremely rare benign tumours and account for only 0.1% of all benign tumours of the lung. Their clinical presentation mimics obstructive lung diseases or malignancy because of their obstructive character, leading to a delay in diagnosis. Methods: We report a retrospective study of 6 cases of endobronchial lipoma diagnosed at our department of pathology. Results: There were 5 male and 1 female patients, aged between 69 and 72 years with a mean of 71 years. cough and dyspnea were the most commonly reported symptom. In all cases, bronchoscopy revealed well-defined submucosal endobronchial lesions and the clinical impres- sion was that of a benign neoplasm. Histologic diagnosis was obtained by endobronchial biopsy in 4 cases and thoracoscopic lobectomy in 2 cases. All lesions showed similar morphology: mature adipose tissue predominated. Examination of all sections did not reveal any areas of cellular atypia or mitoses. Typical features of pulmonary hamartoma were not identified. Conclusion: Endo bronchial lipoma is an extremely rare benign lesion of the respiratory tract which may lead to obstructive complications if unresected. It should be distinguished from fat-rich pulmonary hamar- tomas. All endobronchial lipomatous tumours in the present series behaved in a benign manner. E-PS-21-003 The coexistence of pulmonary hydatid cyst and aspergillosis: an incidental finding R. Ayadi*, B. Emna, H. Ichrak, L. Farah, O. Ismail, A. Ayadi *Hôpital Abderrahmane Mami, Tunisia Background & objectives: The co-existence of hydatid cyst with aspergillosis is extremely rare. There are only a few case reports in the literature on the concomitant of pulmonary hydatid cyst and aspergillosis. The aim was to describe clinocopathological characteristics of this entity. Methods: We report a retrospective study of 8 cases of co-infection of pulmonary hydatid cyst and aspergillosis diagnosed at our department of pathology between 2004 and 2022. Results: There were 5 male and 3 female patients, aged between 19 and 81 years with a mean of 41,57 years. This diagnosis was established by surgical resection in all cases. All lesions showed similar morphol- ogy: laminated membrane of hydatid cyst and infiltration of its wall with septate fungal hyphae with acute angle branching, consistent with aspergillosis. These fungal hyphae were positive with PAS and Gro- cotts methenamine silver. Conclusion: The co-existence of hydatid cyst and aspergillosis is uncommon and the radiological diagnosis may not be helpful in detect- ing the fungal co-infection. The diagnosis is confirmed by histological examination. E-PS-21-004 Sclerosing pneumocytoma of the lung: a case report E. Aydemir*, G.G. Geçmen *University of Health Sciences, Umraniye Training and Research Hos- pital, Department of Pathology, Istanbul, Turkey Background & objectives: Pulmonary sclerosing pneumocytoma (PSP) is a rare benign tumour. It particularly affects middle-aged