Elevated Levels of the Cancer Marker Neuron-Specific Enolase in a Patient With Coexisting Silicosis and Sarcoidosis.

In a periodical medical checkup, a 39-year-old Mongolian underground miner was diagnosed with silicosis based on chest radiography, computed tomography (CT), and work history. Chest radiography showed diffuse bilateral rounded nodules in both lung fields, with upper lobe dominance and large opacities in the right upper zone. Chest CT presented conglomerated massive changes in the right upper lobe and the coalescence of small nodules in the left upper lung. In the blood test, serum levels of the lung cancer marker neuron-specific enolase (NSE) were elevated (24.58 ng/mL). Carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA 21-1) levels were within the reference range. Subsequent to the suspicion of a tumour in the right upper lobe, a right upper lobectomy was performed. The histopathological examination of the lung specimen revealed the coalescence of numerous silica nodules, accompanied by indications of associated sarcoidosis. The histological features suggested the presence of two concurrent pathological processes: silicosis and sarcoidosis. This case demonstrated the combination of three clinical conditions diagnosed in one patient, including complicated silicosis associated with sarcoidosis and elevated serum NSE levels. This case report may serve as a foundation for future investigations exploring the potential of NSE as a marker for silicosis.