The Findings of Pulmonary Nocardiosis on Chest High Resolution Computed Tomography: A single center experience and review of literature

Objectives: Pulmonary nocardiosis is a rare opportunistic infection that is often encountered in immunocompromised patients, in particular those with human immunodeficiency virus (HIV) infection and in solid organ transplant recipients. As the number of immunocompromised patients increase, it is expected that the number of patients with pulmonary nocardiosis will increase. The aim of this study is to review the chest HRCT findings of patients with confirmed pulmonary nocardiosis and to review the imaging features of pulmonary nocardiosis in the literature. Methods: We searched the electronic database of the Royal Hospital, Muscat, Oman for patients with a diagnosis of pulmonary nocardiosis between January 2006 and January 2019. 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: The six patients enrolled in the study were male, aged between 29 and 49 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 has various findings on chest CT. Most common are pulmonary nodules and masses. Awareness of these findings can help radiologists to suggest the diagnosis in the appropriate clinical settings. Keywords: Nodules; Masses; Lung Infections; Opportunistic Pathogen; Pulmonary Nocardiosis; Computed Tomography.