Clinical and Computed Tomography (CT) Characteristics of Pulmonary Nodules Caused by Cryptococcal Infection

PURPOSE: To investigate the clinical and computed tomography (CT) characteristics of pulmonary nodules caused by cryptococcal infection and gain a greater insight and understanding that will reduce misdiagnosis. MATERIALS AND METHODS: A total of 47 patients with confirmed pulmonary cryptococcosis (PC) manifested as nodules were retrospectively enrolled from January 2013 to December 2020. The clinical and CT data of patients with single and multiple nodules were analyzed and compared with emphasis on exploring the characteristics of the solitary ones. RESULTS: Among the 47 patients, single and multiple nodules were detected in 25 (53.2%) and 22 (46.8%) patients, respectively, with similar clinical characteristics. The diameter of solitary nodules was smaller than that of the largest ones of the multiple nodules (P = 0.000). Compared with multiple nodules, less solitary nodules were located in the subpleural zone (P = 0.031) and had a cavity or vacuole (P = 0.049). Regarding the solitary nodules, 22 (88.0%) and 3 (12.0%) were solid and subsolid, respectively. Eighteen (81.8%) solid solitary nodules exhibited either one of air bronchogram or vacuole, satellite lesions, and halo sign. Twenty-three (92.0%) of 25 patients with solitary nodules had follow-up CT data, and most of them had no changes (12, 52.1%) or increased in size and/or density (8, 34.8%), but only a few (3, 13.0%) decreased with or without anti-inflammatory therapy. CONCLUSION: The clinical characteristics of patients with solitary and multiple nodules caused by PC are similar. The solitary nodules are smaller, more scattered, but less necrotic than multiple ones. For solitary nodules with air bronchogram or vacuole, satellite lesions, or halo sign, PC should be considered as one of the differential diagnosis.