Post-COVID-19 Granulomatous Inflammation in the Lung, Distinct From Sarcoidosis: A Report of Two Cases

This report describes two cases of granulomatous lung inflammation following coronavirus disease 2019 (COVID-19), presenting as a sarcoidosis-like reaction with granuloma formation in airspaces and interstitium. Clinical and pathological findings in both cases were similar to but still distinct from sarcoidosis. In the first case, the chest CT of a 55-year-old male with a history of polymerase chain reaction (PCR)-confirmed COVID-19 showed well-defined multiple nodules in the bilateral lung fields. He underwent video-assisted thoracic surgery for diagnostic purposes. The pathological specimen showed loose non-caseous granulomas with mild lymphoplasmacytic infiltration and early fibroblastic proliferation in alveolar spaces. In the second case, a 68-year-old male, who presented with consolidation in the anterior segment of the right upper lobe, underwent bronchoscopy and transbronchial lung biopsy showed non-caseous granulomas with mild lymphoplasmacytic infiltration in the peribronchiolar interstitium. The opacities improved spontaneously in both cases. Further studies are needed to determine whether COVID-19 could cause granulomatous lung inflammation distinct from sarcoidosis.