Nocardiosis in ectopic ACTH syndrome: A case report and review of 11 cases from the literature

Ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS) associated with nocardiosis is rare, and little information is available regarding its clinical characteristics. In this study, the case of a 35-year-old male patient who showed significant cushingoid features and had a cough with yellow phlegm for 1 month is described. Pulmonary computed tomography (CT) scanning and 18F-fluorodeoxyglucose positron emission tomography combined with CT identified two different lesions in the mediastinum and pulmonary region, respectively. The lesion in the mediastinum was finally diagnosed as an ACTH-secreting mediastinal paraganglioma via biopsy. The sputum culture confirmed pulmonary nocardiosis. The patient was effectively treated with complete tumor resection following the treatment of nocardiosis using trimethoprim-sulfamethoxazole. Following the present case, 11 additional cases of nocardiosis in EAS were identified in the literature and their clinical characteristics were compared and evaluated. It may be concluded that, although Nocardia remains a rare opportunistic infection pathogen in EAS, it is necessary to consider nocardiosis as a diagnosis for patients with pulmonary imaging findings of cavity, consolidation or nodule, particularly when there are brain and extra-pulmonary lesions as well as a poor response to regular treatment.