Peripheral subpleural intrapulmonary lymph nodes. Apropos of a clinical case and an anatomical case

The authors report the case of a round, peripheral radiographic opacity ("coin lesion" of English-language authors) which after surgical excision was found to be an intrapulmonary lymph node. In an anatomical study on the lymphatic drainage of pulmonary segments in adults, a similar lesion was found among 483 injected segments. A review of the literature yielded 27 similar cases which are described in detail. These lymph nodes are probably more frequent than is generally believed, as shown by an experimental radiolymphographic study. Such clinical findings will no doubt be rendered more numerous by the improved sensitivity of new medical imaging techniques. Despite hypotheses put forward by the authors, the presence of these lymph nodes, which seem to be acquired by the adult lung, has not yet been explained.