On the possible ontogeny of the cells of a "granular cell tumor" of the human trachea. In a young patient affected with pulmonary tuberculosis during bronchoscopy a "granular cell tumor" of the membranous part of trachea was occasionally evidentied. After pathologic examination, the specimen is analyzed in order to assess the kind of cells that are present in the lesion: the ultrastructural and immunohistochemical study shows Schwann cells which particularly well developed lysosomal complement.