Juvenile nasopharyngeal angiofibroma is a tumor with a predilection for adolescent boys. It has been shown to contain cytosolic androgen receptors and to regress with estrogen therapy; however, the results have not been consistent. Extensive investigation has been unable to settle this issue in patients owing, in part, to the rarity of these tumors. We have attempted to establish a tumor model for juvenile nasopharyngeal angiofibroma by transplanting the tumor into the subdermal space of athymic mice and also by culturing it in vitro, to study the effect of hormonal manipulation. The tumor did survive in male and female athymic mice but has failed to grow. Androgen treatment of the mice of either sex did not alter its survival or growth behavior. The in vitro tissue culture grew fibroblastoid cells that were not stimulated by androgen supplementation. This study suggests that factors other than androgens are at least complementary, if not essential, in promoting the growth of juvenile nasopharyngeal angiofibroma in tumor models, and that androgens are not, in and of themselves, sufficient growth stimuli.