Histogenetic and morphological in vivo and in vitro data concerning androgen-estrogen-induced scent gland tumor in the Syrian hamster.

The scent gland tumor of the Syrian hamster is induced by exogenous androgen and estrogen. Microscopic nodules are induced normally in old males by endogenous androgen. The histogenesis of the scent gland tumor is complex and not completely understood. In this study microscopic preneoplastic nodules and macroscopic tumors were studied by light and electron microscopy, and the macroscopic tumors were grown in tissue culture on collagen-coated coverslips and on sponge foam matrices by the organ culture method. The cultures were fed with an unfiltered fetal calf serum-bovine serum ultrafiltrate medium, which contained endogenous androgen-estrogen, 110-100 pg and could maintain growth without additional androgen-estrogen. Exogenous androgen-estrogen was also added to some cultures. Scent gland tumors grown in organ culture contained cells of two shapes, spindle and ovoid arranged in cords. Cultures on coverslips showed radiating outgrowths of spindle cells suggesting either mesenchymal or Schwann cells. By electron microscopy, both in vivo and in vitro preneoplastic and tumor samples contained cells with segments of basal lamina, micropinocytotic vesicles, and junctional complexes. These features were similar to those of poorly differentiated experimental malignant rat schwannomas maintained in similar in vitro systems. Tumors grown in vivo and in vitro were associated with collagen fibrils with a periodicity ranging from 400 to 1075 A. The evidence reported in this paper suggests that one component of the scent gland tumor is an androgen-estrogen-induced poorly differentiated schwannoma.