We reported a case of complicated silicosis that occurred in a glass manufacturing plant worker who had presumably been exposed to low-concentration free silica for almost 20 years. To the best of our knowledge this report is the first in the Republic of Korea. The physician's first impression was cancer since the enlargement of neck and supraclavicuar lymph nodes had clearly progressed and metastasis was suspected in ultrasonography. However, it turned out to be reactive hyperplasia and anthracosis. Although lung cancer was suspected and tests were performed in 2 hospitals due to repetitive cough and dyspnea, along with weight loss of approximately 10% over the course of 7 months, the patient was eventually diagnosed with complicated silicosis and pneumothorax occurred after 1 year. Herein, we report this case with a literature review.