S-100 protein-positive Langerhans cells in various human lung cancers, especially in peripheral adenocarcinomas.

The appearance of S-100 protein-positive Langerhans cells was studied in 90 cases of various lung cancers by an immunohistochemical method. S-100 protein-positive dendritic cells were frequently observed in many adenocarcinomas, especially in those subclassified as bronchiolar cell or type II alveolar cell type. However, no S-100 protein-positive cells were found in "goblet cell type" adenocarcinoma. In some cases of squamous cell carcinoma and large cell carcinoma, these dendritic cells were also observed though they were fewer in number. In all cases of small cell carcinoma, however, S-100 protein-positive dendritic cells were rare. Electron microscopic study of two adenocarcinomas clearly demonstrated many Birbeck granules in the cytoplasm of S-100 protein-positive dendritic cells and confirmed that S-100 protein-positive cells in lung cancer were identical with Langerhans cells.