Intrapulmonary lymph nodes in South African miners—an autopsy survey

BACKGROUND: Knowledge on intrapulmonary lymph nodes (IPLNs) is still limited. Progress in imaging techniques has enabled easier, more frequent visualization of IPLNs so that a more comprehensive understanding of these nodes is necessary. METHODS: Microscopic slides of lung tissue from 2,337 dust-exposed South African miners autopsied in 1975 were reviewed to identify IPLNs. The prevalence of IPLNs was calculated and histopathological changes in IPLNs and the surrounding lung parenchyma were described. Pathological changes of IPLNs were correlated with those of the surrounding pulmonary parenchyma. RESULTS: IPLNs were found in 86 of the miners (3.7%). Silicotic nodules were seen in IPLNs in 32 of the 86 cases (37.2%), in the majority of which (21/32; 65.6%) the surrounding lung parenchyma was almost normal. CONCLUSION: IPLNs are not uncommon among dust-exposed individuals. Silicotic fibrosis of IPLNs appears to precede pulmonary parenchymal disease.