[Sarcoid reaction with focal interstitial fibrosis in a COVID-19 patient with persistence of Sars-Cov-2 virus nucleocapsid and adhesion proteins in sarcoid granulomas and lung tissue].

A case report of pulmonary sarcoidosis with fibrosis after COVID-19 is presented. Morphologic and immunohistochemical analysis of lung biopsies for Sars-Cov2 nucleocapsid and adhesion proteins was performed. Virus proteins were detected in alveolar macrophages, second-order pneumocytes and bronchiolar epithelium, also in granuloma-associated macrophages, multinucleated Pirogov-Langhans cells, indicating Sars-Cov2 persistence. Meanwhile, release of pro-inflammatory cytokines by granuloma cells and interstitial macrophages resulted in tissue damage and pulmonary fibrosis.