Diffuse panbronchiolitis with multiple tumorlets. A quantitative study of the Kultschitzky cells and the clusters.

An autopsy case of diffuse panbronchiolitis with incidentally observed multiple tumorlets was reported. Quantitative study revealed the distribution and number of single Kultschitzky cell and its cluster. These cells were more frequently observed in the present case than in 20 control cases, and moreover, they tended to occur more frequently in the pulmonary segment in which tumorlets were found and there was an apparent transition of them into tumorlets. Immunohistochemically, gastrin-releasing peptide, calcitonin, and serotonin were demonstrable in the cells which consisted of both tumorlets and Kultschitzky cell clusters. It is suggested that the Kultschitzky cell is a precursor cell of the tumorlet and that tumorlet is benign, being hyperplastic in nature.