A previously healthy 55-year-old female dentist, who had never smoked, was admitted to hospital with transient pneumonia and bilateral consolidation (mainly in the right upper and middle lobes) on the chest X-ray. Pneumonia was resolved with antibiotics treatment. Throughout her professional life, she has been exposed to various types of volatile organic and inorganic compounds. In addition to biological materials, these compounds include silica, heavy metals, and acrylic plastics. She worked with dental prosthesis, various dental operations, and compounds which are used in tooth filling. There was no other specific exposure suspected such as beryllium, aluminum, etc., neither other potential exposures from other jobs or hobbies.
Lung function assessments showed a FEV1 of 4.2 L (118% of predicted value), a FVC of 3.3 L (107%), and a FEV1/FVC of 72%. Contrast-enhanced thoracic and abdominal CT revealed an 8 mm nodule in the right upper lobe, growing into the surrounding lung parenchyma and a 7 mm nodule in the interlobular fissure between the right upper lobe and middle lobe. Two pleural nodules with 4 mm in size were seen in the right-side dorsal aspect of the pleura. There was no pleural fluid or pathologically enlarged lymph nodes in the axilla or mediastinum.
PET-CT revealed faint metabolic activity in a 9-mm nodule in the right upper lobe, suggesting a Herder model cancer probability of 52%. Therefore, the patient underwent CT-guided biopsy. The first biopsy found suspicious cells, but the second biopsy showed no signs of malignancy. No granulomas were present, and the patient was referred for wedge resection by video-assisted thoracoscopic surgery. Histological examination showed several 3-12 mm necrotizing granulomas; however, no malignancy. Bacterial culture and polymerase chain reaction analysis for Mycobacterium tuberculosis from surgical specimens were negative. Various blood tests and clinical examinations showed no signs of infectious diseases, Wegener's granulomatosis, rheumatoid arthritis, or sarcoidosis. The multidisciplinary team concluded that the patient had pulmonary granulomas secondary to occupational inhalation of silica and other inorganic dust. The patient was referred for control CT scans at 3 and 9 months, and the results were unchanged. The patient was asymptomatic.