Intrapulmonary lymph nodes: CT and pathological features

Intrapulmonary lymph nodes are not uncommon and may be seen frequently in high quality computed tomography (CT) images and chest radiographs. We report four patients, older than 55 years, who had a long history of heavy smoking. Four intrapulmonary lymph nodes were located in the subpleural region (within 3 mm of the visceral pleural surface) of the right or left lower lobes. The lymph nodes were ovoid or round, homogeneous, well-defined and ranged from 9 to 10 mm in diameter. In one case, coexistent small nodules in the same or in other lobes on initial CT studies increased slightly in size over the following 3 years. All nodules contained lymphoid follicles and anthrocotic pigment, and in one case adjacent small aggregates of lymphocytes along interlobular septa were seen. Intrapulmonary lymph nodes have non-specific CT and clinical features. Follow-up CT may be useful in patients with suspected intrapulmonary lymph nodes.