Pulmonary aspergillosis in immunocompetent patients without air-meniscus sign and underlying lung disease: CT findings and histopathologic features

Abstract

Pulmonary aspergillosis in immunocompetent patients has been described as a saprophytic infection with pre-existing lung lesions showing an air-meniscus sign on chest radiograph or CT scans. There have been rare articles dealing with pulmonary aspergillosis in immunocompetent patients without pre-existing lung lesions. To evaluate the CT findings of pulmonary aspergillosis in immunocompetent patients without air-meniscus and underlying lung disease and to correlate the CT findings and pathologic features of pulmonary aspergillosis in these patients. A total of seven surgically proven pulmonary aspergillosis found in immunocompetent patients without an air-meniscus and underlying lung disease (M:F = 1:6; mean age 63.4 years) were included. On CT, the lesion shape, margin, type, location, diameter, presence of satellite nodules, presence of CT halo sign or hypodense sign, and interval growth were evaluated. Histopathologic features of each lesion were classified as one of the following; primary aspergilloma, chronic necrotizing pulmonary aspergillosis, or invasive pulmonary aspergillosis. Correlation between CT findings and pathological features was performed. All lesions presented as a nodule or mass unable to differentiate from malignancy. Most lesions had well-defined margins (n = 4), appeared as solid lesions (n = 7), and were located in the upper lobe (n = 5). Mean diameter of lesions was 2.3 cm. Satellite nodules (n = 2), CT halo sign (n = 1), and hypodense sign (n = 4) were found. Only one lesion increased in size during follow-up. Lesions were pathologically classified as primary aspergilloma (n = 3) and chronic necrotizing pulmonary aspergillosis (n = 4). The hypodense sign on CT was pathologically proved as dense fungal hyphae filled in bronchus and CT halo sign as parenchymal hemorrhage. Pulmonary aspergillosis predominantly presented as a nodule or mass mimicking malignancy in the upper lobes on CT scan in elderly without underlying lung disease and immunosuppressive conditions except for age, and was histopathologically revealed to be either primary aspergilloma or chronic necrotizing pulmonary aspergillosis.