[Histogenetic considerations of experimentally induced adenomatoid tumor-like nodules produced by sex steroids].

Glandlike structures with intervening fibrous stroma were observed in about 20% of subperitoneal nodules produced in the abdominal cavities of guinea pigs treated with various doses of estradiol benzoate (E) for 3 months. These glandlike structures were composed of cells resembling mesothelium, ciliated cells, cells with mucin in the cytoplasm and cells with a squamous appearance. Glandlike structures similar to those following estrogen treatment alone were also observed in about 20% of the nodules produced in the guinea pigs by pre-treatment with E and followed by combination treatment with E and progesterone (P) for 1 to 3 months. However, the glandlike structures were composed only of cells resembling mesothelium and cells with cilia. Both of these glandlike structures resembled adenomatoid tumors. We therefore conjecture that the formation of gland-like structures in the subperitoneal nodules is the result of mesothelial inclusions and their proliferation, and that some of these mesothelial cells were differentiated into ciliated, mucinous and squamous cells by estrogen.