Chronic Graft versus Host disease involving the lung: CT scan features

Patients diagnosed with pulmonary cGVHD between 2010 and 2023 were included in this observational retrospective study. Inclusion criteria were: age above 18, and available CT scan at diagnosis of cGVHD of the lung. Hematological history, treatment, transplant time, and symptoms were recorded. CT scans were evaluated by two Radiologists and findings classified according the Glossary of Fleischner society. cGVHD presented with three main patterns: acute/subacute lung injury, bronchiolar pattern, and restrictive pattern with pleuroparenchymal fibroelastosis (PPFE). Acute/subacute lung injury group (n=5) exhibited features such as ground glass, crazy paving, reverse halo sign, and perilobular pattern. Bronchiolar presentation (n=20) ranged from centrilobular nodules to extensive mosaic attenuation. Restrictive phenotype was mainly standalone PPFE or PPFE with signs of airways disease (n=12) and fibrotic interstitial lung disease (n=2 definite UIP; n=1 probable UIP). Onset occurred around 15 months, 3 years, and later, respectively. This study highlights CT's role in defining cGVHD's clinical-radiological phenotypes. Different patterns are associated with diverse onset times.