Non-tuberculous Mycobacterium Infection Associated with Artificial Stone Silicosis: A Case Series

The incidence of non-tuberculous mycobacterium (NTM) infections has been rising in patients with chronic lung diseases. These infections cause significant morbidity, mortality, and elevated healthcare costs due to challenges in recognition, delayed diagnosis, and treatment. While NTM infections in natural stone silicosis are documented, the incidence in artificial stone silicosis remains unexplored despite increasing exposure to silica dust.

To describe the clinical, radiological, and pathological features of NTM infections in patients with artificial stone silicosis and emphasize the importance of early diagnosis.

We reviewed the database of a tertiary medical center in Israel from 2010 to 2024 and identified patients with occupational artificial stone silicosis diagnosed with NTM infection.

We found eight patients with occupational artificial stone silicosis, all male, aged 42-74 years. Key symptoms included dyspnea, cough, weight loss, and fever. Computed tomography revealed mediastinal lymphadenopathy, progressive massive fibrosis, calcifications, pulmonary cavitations, pleural thickening, traction bronchiectasis, pulmonary nodules, and honeycombing. Biopsies showed silicotic nodules, birefringent crystals, pulmonary alveolar silico-proteinosis, fibrosis, and honeycombing. Four patients received NTM-targeted antibiotics, and six underwent lung transplantation. Four patients died.

Artificial stone silicosis may be associated with NTM infections. Early diagnosis requires a high degree of clinical suspicion. New or worsening respiratory or systemic symptoms in patients with silicosis should prompt further microbiological evaluation, including sputum culture or bronchoalveolar lavage. Further studies are needed to assess the incidence of NTM infections in this population.