A Frequently Missed Pulmonary Infarction: Clinical and (18)F-FDG PET/CT Manifestation of Hilar Tumor–Induced Pulmonary Infarction

This study aimed to summarize the clinical and (18)F-FDG PET/CT manifestations of hilar tumor–induced pulmonary infarction. METHODS: A retrospective analysis was performed on patients with hilar masses who underwent FDG PET/CT scans between July 2015 and January 2021 and had complete clinical data. Pulmonary infarction was confirmed by concurrent chest CT and imaging follow-up or pathology. RESULTS: A total of 58 patients (mean age, 56 [SD, 13] years; 44 males) with 122 infarcts were included in the study. Hilar masses were mostly associated with small cell lung cancer (64%). The most common clinical manifestations were cough (64%) and hemoptysis (36%). Most patients (62%) had multiple pulmonary infarcts. The CT findings of pulmonary infarcts included the “Hampton hump” (48%) and patchy consolidation (52%). The density of infarcts included “bubbly consolidation” (61%) and “homogenous consolidation” (39%). The metabolic activity of 95 infarcts (78%) was higher than lung parenchyma, with the SUV(max) of 3.3 (SD, 1.1). The metabolic patterns on PET/CT were “rim sign,” “mismatch between PET and CT,” and “no metabolism.” Pulmonary vein involvement was found in 25 patients (43%), pleural effusion in 22 patients (38%), and the pleural curvilinear sign in 8 patients (14%). CONCLUSIONS: The clinical manifestations of hilar tumor–induced pulmonary infarction are not specific, and (18)F-FDG PET/CT could be an effective diagnostic tool.