case_images: PMC11821482_01
case_images: Enhanced chest CT of the patient before thymectomy. (A) Small nodules were distributed throughout both lungs, with a predominant presence in the lower lobes (pulmonary window). (B) The thymus region (red arrow) located in the anterior mediastinum exhibited increased density and heterogeneity, with the enhanced scan revealing a slight enhancement.
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case_images: Chinese man presented to the thoracic surgery department of our hospital on October 24, 2020, with recurrent cough, expectoration, and shortness of breath. Chest-enhanced CT revealed a mediastinal mass and small scattered nodules in the lungs ( Figure 1 ).
case_images: Chest CT scans of the patient. (A-C): The chest CT (2021-1-28) during the period of thymectomy and radiation showed that the distribution of small nodules in both lungs increased significantly, accompanied by changes in tree bud signs. Additionally, an emerging consolidation opacity in the middle lobe of the right lung. (D-F): The chest CT (2021-04-03) after 25 thymectomies and radiation showed that the number of nodules and the presence of tree bud signs in both lungs exhibited a greater degree of progression. The area of consolidation opacity in the middle lobe of the right lung enlarged, while a novel consolidation opacity emerged in the upper lobe of the right lung. (G-I): After treatment with azithromycin and steroids for three months, the chest CT showed that the small nodules were reduced, and the consolidation of the upper lobe and middle lobe of the right lung was absorbed.
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case_images: December 17, 2020, to February 3, 2021. During radiation therapy, his cough, expectoration, and shortness of breath gradually worsened, and chest CT revealed new consolidation in the middle lobe of the right lung and a significant increase in small pulmonary nodules compared to the pre-radiation period ( Figures 2A-C ). A CT scan ( Figures 2D-F ) revealed multiple diffuse small nodules in both lungs, accompanied by tree-in-bud signs. At the follow-up on July 1, 2021, repeat chest CT showed resolution of consolidations in the right middle and upper lobes, a decrease in the number of small nodules, and the presence of improved tree-in-bud signs in both lungs ( Figures 2G-I ).
case_images: Timeline of the patient's treatment.
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case_images: The details of the diagnosis and treatment are shown in  Figure 3 .