A Case of Pulmonary Siderosis Mimicking Metastatic Lung Cancer

Abstract

Pulmonary siderosis is a pneumoconiosis caused by chronic iron inhalation. A diagnosis of pulmonary siderosis is based on a patient history of iron inhalation, on chest radiographic findings, and on accumulation of iron oxide in macrophages within the lung. A typical radiographic finding of pulmonary siderosis includes ill-defined micronodules that are diffusely distributed in the lung. We experienced a 52-year-woman with a 1.3×1.5-cm mass in the left upper lobe with multiple nodules in both lungs. Because the radiographic findings were atypical, we conducted a video-assisted thorascopic lung biopsy procedure to exclude the diagnosis of metastatic lung cancer. After confirming iron deposition in the lung tissue and knowing the patient's occupational history of welding iron, we concluded that this was a case of pulmonary siderosis.