Miliary Pattern on Chest Radiography: TB or not TB?

Abstract

A 37-year-old nonsmoking Ecuadorian mason presented with a 3-month history of productive cough, fever, night sweats, shortness of breath, and weight loss. His symptoms were becoming progressively worse, with substantial decline in functional ability. He had blood-tinged sputum. Physical examination revealed tachypnea, and chest radiography on admission revealed scattered crackles throughout the right lung fields. Results were positive for the purified protein derivative (tuberculin) test and negative for the acid-fast bacillus smear and cultures. Computed tomography of the chest showed diffuse subcentimeter nodules in both lungs fields and an infrahilar mass in the right lung. Bronchoscopic biopsy of the middle and lower parts of the right lung showed poorly differentiated primary lung adenocarcinoma. Palliative care was accepted, and the patient died approximately 1 month later. The differential diagnosis of miliary pattern on chest radiography includes miliary tuberculosis (TB), histoplasmosis, sarcoidosis, pneumoconiosis, bronchoalveolar carcinoma, pulmonary siderosis, and hematogenous metastases from primary cancers of thyroid, kidney, trophoblast, and some of the sarcomas.1,2 Primary lung cancer with hematogenous spread may cause miliary shadows. Although nonspecific, this radiographic finding may be helpful in certain clinical scenarios. In our case, diagnosing TB is tempting, but tissue diagnosis is essential for accurate management.