The findings of pulmonary nocardiosis on chest high resolution computed tomography : single centre experience and review of literature

Objectives: Pulmonary nocardiosis is a rare opportunistic infection that is often encountered in immunocompromised patients, in particular those with the HIV infection and in solid organ transplant recipients. As the number of immunocompromised patients increase, the number of patients with pulmonary nocardiosis is also expected to increase. This study aimed to analyse both the chest high resolution computed tomography (HRCT) findings of patients with confirmed pulmonary nocardiosis and review the imaging features of pulmonary nocardiosis in the literature. Methods: This retrospective study was conducted at The Royal Hospital, Muscat, Oman, to identify patients with a diagnosis of pulmonary nocardiosis between January 2006 and January 2019. Accordingly, nine patients with pulmonary nocardiosis were identified, but three patients were excluded as no chest HRCT images were available. Patient clinical presentation was recorded and chest HRCT images were retrospectively reviewed. Results: A total of six patients were enrolled in this study. All were male and with a mean age of 41 ± 11 years. Three patients were immunocompromised, two of whom had undergone a renal transplant. The main HRCT findings were cavitary nodules/masses, non-cavitary nodules/masses, septal thickening, centrilobular nodules, ground glass opacities, consolidation, pleural effusion, pleural thickening, enlarged lymph nodes and necrotic lymph nodes. Conclusion: Pulmonary nocardiosis shows various findings in a chest CT, the most common of which are pulmonary nodules and masses. Awareness of these findings can help radiologists with a diagnosis in the appropriate clinical settings.