Clinical Characteristics and Etiologies of Miliary Nodules in the US: A Single-Center Study

Background: Miliary nodules have been typically described as a radiological manifestation of disseminated tuberculosis. However, miliary nodules are known to occur in a wide variety of conditions. The primary objective of the study was to identify clinical characteristics and etiologies of miliary nodules within our institution. Methods: Using International Classification of Diseases, Ninth and Tenth Revision codes, electronic medical records were used to retrospectively identify 53 patients who fulfilled criteria of miliary nodules over the last 10 years. Demographic and clinical data were extracted for all the patients in this cross-sectional study. Results: The diagnosis of tuberculosis was made in 15 (28.3%) patients, sarcoidosis in 12 (22.6%), silicosis in 7 (13.2%), extrathoracic malignancy in 5 (9.4%), and histoplasmosis in 4 (7.6%) patients. Four of 9 HIV patients had histoplasmosis. There was 1 case each of hypersensitivity pneumonitis, Pneumocystis jiroveci pneumonia, Mycobacterium-avium complex, Epstein-Barr virus pneumonia, cryptococcosis, aspergillosis, and primary lung cancer. Sputum was positive for acid fast bacilli in 4 cases (28%), and bronchoscopy had a 57% successful yield in miliary tuberculosis. Conclusion: Our study is the largest single-center data review evaluating the etiology of miliary nodules within the United States; most of the data exist in case reports.