[Endocrine cells in Walthard's cell rests]

Walthard cell nests have been systematically examined for the presence of some endocrine cell types using histochemical and immunohistochemical techniques. Serotonin immunoreactive cells were the only endocrine cells demonstrated in this site. These cells were immunocharacterized using a peroxidase-antiperoxidase technique. This finding reinforces the homology with transitional epithelium (urothelium) of urinary tract and Brenner tumors. In all these structures, the abundance of endocrine cells seems to be related to the intensity of the proliferative process affecting the transitional epithelium.