UTERINE SARCOMAS IN CBA MICE INDUCED BY COMBINED TREATMENT WITH 1,2-DIMETHYLHYDRAZINE AND ESTRADIOL DIPROPIONATE - LIGHT AND ELECTRON-MICROSCOPY

Three uterine sarcomas induced by combined treatment (1,2-dimethylhydr azide and estradiol dipropionate) in CBA mice were examined by light a nd electron microscopy. Histologically the tumours consisted either of loose areas with stellate cells or of solid cellular areas. These wer e formed of elongated cells of the fibroblastic type and rounded cells with clear nuclei and abundant cytoplasm without clearly discernible bodies. Ultrastucturally, undifferentiated mesenchymal cells and cells with the features of fibroblasts and myofibroblasts were distinguishe d. The tumours described bear resemblance to human endometrial stromal sarcomas and are interpreded as sarcomas originating from immature me senchymal cells differentiating mainly in the direction of cells of th e fibroblastic type. Certain similarities with fibrous histiocytomas a re noted.