analysis of chest computed tomography manifestations of non-mycobacterium tuberculosis induced granulomatous lung diseases

Purpose: To analyze the chest computed tomography (CT) manifestations of non-Mycobacterium tuberculosis (TB) induced granulomatous lung disease (GLD) with their clinical presentations and laboratory test results. Methods: A total of 55 patients had chest CT scan during a period from June 2010 to January 2016. We retrospectively compared the location, morphology and other specific features of the lesions that were pathologically diagnosed as non-TB induced GLD. Clinical presentations and laboratory results were also documented. Results: Infectious causes of GLD identified are mainly pulmonary cryptococcosis (n = 8, 14.5%) and pulmonary actinomycosis (n = 3, 5.5%). For non-infectious causes, the most common cause is pulmonary sarcoidosis (n = 27, 49.1%). Symptoms frequently observed include cough (n = 39, 70.9%) and expectoration (n = 30, 54.4%). Lesions due to GLD are mainly multiple and have bilateral distribution on chest CT. These findings are particularly prominent for non-infectious GLD. Lesions in non-TB induced infectious GLD are often unilateral. The morphology of lung lesions is mostly nodules, but lesions can also be masses, consolidations or ground-glass opacity based on the underlying etiology. Nodules are prominent in lungs affected by sarcoidosis along with thoracic lymphadenopathy. Nodules are also seen in non-TB induced infectious GLD, but they are rarely accompanied by hilar lymphadenopathy. Conclusion: Chest CT could be helpful in diagnosis of the underlying causes of the disease. Nevertheless, chest CT is still insufficient to provide a diagnosis alone due to its unsatisfactory specificity. Confirmation of the diagnosis still relies on histopathological exam of tissue samples. Keywords: Non-TB induced granulomatous lung disease, Chest computed tomography (CT), Pulmonary sarcoidosis, Pulmonary fungal infections, Pulmonary lesions