[Pathological features and diagnostic significance of lung biopsy in occupational lung diseases]

Objective: To investigate the clinicopathological characteristics of occupational lung diseases, to reduce the missed diagnoses and misdiagnoses of the diseases and to help standardize the diagnosis and treatment of these patients. Methods: A total of 4 813 lung biopsy specimens (including 1 935 consultation cases) collected at the Department of Pathology, Nanjing Drum Tower Hospital, Nanjing, China from January 1st, 2017 to December 31th, 2019 were retrospectively analyzed. Among them, 126 cases of occupational lung diseases were confirmed with clinical-radiological-pathological diagnosis. Special staining, PCR and scanning electron microscopy were also used to rule out the major differential diagnoses. Results: The 126 patients with occupational lung diseases included 102 males and 24 females. All of them had a history of exposure to occupational risk factor(s). Morphologically, 68.3% (86/126) of the cases mainly showed pulmonary fibrotic nodules, dust plaque formation or carbon end deposition in pulmonary parenchyma. 16.7% (21/126) of the cases mainly showed welding smoke particle deposition in the alveolar cavity and lung interstitium while 15.1% (19/126) of the cases showed granulomas with fibrous tissue hyperplasia, alveolar protein deposition or giant cell interstitial pneumonia. The qualitative and semi-quantitative analyses of residual dust components in the lung under scanning electron microscope were helpful for the diagnosis of welder's pneumoconiosis and hard metal lung disease. Conclusions: The morphological characteristics of lung biopsy tissue are important reference basis for the clinicopathological diagnosis and differential diagnosis of occupational lung diseases. Recognizing the characteristic morphology and proper use of auxiliary examination are the key to an accurate diagnosis of occupational lung diseases on biopsy specimens.