[Histogenesis of benign pleomorphic mesenchymal tumors].

Benign pleomorphic mesenchymal tumours (lipoma, fibroblastoma) are defined by large cells which have multiple peripheral nuclei and thus remind of a flower. Similar cells were already previously detected by Mirejovský as a reactive change in polypous processes. We assume that these cells may occur not only in non-tumours but also in tumours where similar stromal conditions exist as in polyps. Therefore pleomorphic giant cells are of no value for assessment of the histogenesis of tumours. Nevertheless giant cell pleomorphic reactive changes may be mistaken for atypical tumours and therefore their knowledge is of practical importance.