Akademik Veri Yönetim Sistemi
37th European Congress of Pathology, Vienna, Avusturya, 4 - 07 Eylül 2025, ss.251-252, (Özet Bildiri)
Background & Objectives: Amyloidosis encompasses a group of dis orders characterized by extracellular deposition of misfolded proteins (amyloid), leading to progressive organ damage. Definitive diagnosis traditionally relies on invasive biopsies for histopathological identifi cation of amyloid deposits. Congo red staining, with its characteris tic apple-green birefringence under polarized light, remains the gold standard for confirmation. Minimally invasive cytological specimens, such as bronchial aspirates, present a promising diagnostic alternative but require further systematic validation. This case study aims to: (1) demonstrate the utility of cytological specimens in diagnosing amy loidosis, (2) highlight the role of Congo red staining in differentiating amyloid from mimicking entities in bronchial samples, and (3) empha size that amyloidosis may be rarely observed in cytology. 1 3 Virchows Archiv Methods: A 51-year-old woman with Sjögren’s syndrome presented with dyspnea and cough. Thoracic CT revealed bilateral nodular lesions, central consolidations, bronchiectasis, and a 4 cm thin-walled cavitary lesion in the left lower lobe. Suspecting granulomatous/fun gal infection or malignancy, fiberoptic bronchoscopy was performed. Aspirated material was processed using the ThinPrep method for cytol ogy: smears were Papanicolaou-stained, and cell blocks were prepared with haematoxylin-eosin. Congo red staining was performed, and slides were examined under polarized light microscopy to confirm amyloid deposition. Results: Cytological smears revealed bronchial epithelial cells, his tiocytes, and lymphocytes. Cell block analysis identified eosinophilic amorphous material admixed with histiocytes and epithelial cells. Congo red staining demonstrated red-orange positivity under light microscopy, with characteristic apple-green birefringence under polar ized light, confirming amyloid. The findings distinguished amyloid from differentials such as mucus, alveolar proteinosis, fibrin, and cor pora amylacea. Conclusion: This case underscores the diagnostic efficacy of Congo red staining in cytological specimens obtained via minimally invasive bronchoscopy. It highlights the critical role of histochemical methods in differentiating amyloid from morphologically similar entities in pul monary samples. Integrating Congo red into cytopathology workflows enhances diagnostic precision, reducing reliance on invasive biopsies in suspected amyloidosis cases.