Intermittent lymph-node metastases (''skipping'') in malignant lung tumors

In 50 lung cancers (25 small cell lung cancers, 17 squamous cell carcinomas, & adenocarcinomas) pulmonary, mediastinal and cervical lymph node-metastases were analyzed. Lymph-node ''skipping'' was demonstrated in 46% of the investigated tumors. In seven of these cases the lymph nodes were skipped, which showed complete hyalinization as a consequence of preexisting anthracosilicosis. In 5 other tumors additional lymph nodes with preserved structure were skipped by the metastatic process. Fibrosis of lymphatic tissue after tuberculosis or exposure to ionizing radiation were further reasons for lymph-node skipping. The skipping of intact lymph nodes can be explained by anatomically demonstrable intra- and perinodal short circuit connections, Apart from that, preexisting lymph node changes (silicosis, fibrosis) play an important part.