Primary Pulmonary Diffuse Large B-cell Lymphoma

We present unique fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) PET/CT findings of primary pulmonary diffuse large B-cell lymphoma (DLBCL). A 72-year-old man presented with two weeks of fever and mild upper respiratory symptoms. Initial CT and ¹⁸F-FDG PET/CT were unremarkable save for non-specific dependent ground glass opacities (GGO). His condition progressed with no unifying diagnosis, and repeat imaging three months later showed progression in the lungs. CT-guided lung core biopsy was performed. Histology showed primary pulmonary DLBCL. This case aims to highlight a unique cause of diffuse GGO, as early recognition is crucial to prevent delays in treatment.