Summary
Ear lobe tumours which develop in ovariectomized rats following oral administration of dimethylbenzanthracene have been investigated under the light and the electron microscope. They occur with a 25% incidence after six to eight months and appear as small firm rapidly growing nodules measuring up to 0.5 cm in diameter. By light microscopy these neoplasms are seen to arise in the deeper layers of the derma near the cartilage plate and appear as a relatively uniform, non encapsulated, fasciculated growth consisting of slightly acidophilic spindle cells in a sparse network of fine collagen fibers. Under the electron microscope, the tumour cells are highly pleomorphic, uncohesive, exhibiting intertwined cytoplasmic processes. Their cytoplasm show extreme vacuolization; at first they would appear as secretory cells but on close examination it becomes evident that we are dealing with a multitude of autophagic vacuoles. In the absence of palisadic arrangement, of cholinesterase activity or of other ultrastructural features of neurilemmal cells, we are enclined to believe that these neoplastic growth do not derive from Schwann cells and should be classified in the category of mesenchymal tumours. The term dermatofibrosarcoma seems appropriate for these neoplastic growths.
Résumé
Les tumeurs du pavillon de l’oreille induites chez le rat ovariectomisé par l’administration orale de diméthylbenzanthracène ont fait l’objet d’une étude en microscopie optique et électronique. Elles surgissent entre le 6e et le 8e mois avec une fréquence de 25%, ont une forme globuleuse et leur diamètre ne dépasse guère 0,5 cm. Ces tumeurs naissent dans les profondeurs du derme au voisinage du cartilage auriculaire, se développent rapidement sans capsule conjonctive et sont constituées par des cellules fasciculées légèrement acidophiles et quelques rares fibrilles collagènes. En microscopie électronique, les cellules sont pléomorphiques, peu cohésives et montrent de multiples prolongements cytoplasmiques enchevêtrés au sein d’une substance interstitielle raréfiée. Leur cytoplasme est creusé de nombreuses vacuoles d’autophagie. En l’absence d’une disposition cellulaire palissadique, d’activité cholinestérasique et d’une conformation ultrastructurale caractéristique des cellules de Schwann, nous croyons que ces néoplasmes n’offrent pas les indices classiques d’une origine nerveuse et nous sommes enclins à les ranger dans la catégorie des croissances mésenchymateuses. Le terme de dermatofibrosarcome nous paraît approprié pour étiqueter ces nodules tumoraux.
Similar content being viewed by others
Bibliographie
Barka, T., Anderson, P. J.: Histochemistry. Theory, practice and bibliography. New York: Hoeber 1963.
Cawein, M. J., Sydnor, K. L.: Suppression of cellular activity in the reticuloendothelial system of the rat by 7, 12-dimethylbenz(a) anthracene. Cancer Res.28, 320–327 (1968).
Dao, T. L.: Studies on mechanism of carcinogenesis in the mammary gland. In: Progress in experimental tumor research, II, p. 235–261. Basel: S. Karger 1969.
Heimann, R., Heuson, J. C., Coune, A.: Tumors developing in oophorectomized Sprague-Dawley rats after a single gastric instillation of 7, 12-dimethylbenz(a) anthracene. Cancer Res.28, 309–313 (1968).
Huggins, C., Briziarelli, G., Sutton, H.: Rapid induction of mammary carcinoma in the rat and the influence of hormones on the tumors. J. exp. Med.109, 25–42 (1959).
— Fukunishi, R.: Mammary and peritoneal tumors induced by intraperitoneal administration of 7, 12-dimethylbenz(a) anthracene in newborn and adult rats. Cancer Res.23, 785–789 (1963).
— Grand, L. C.: Neoplasms evoked in male Sprague-Dawley rat by pulse doses of 7, 12-dimethylbenz(a) anthracene. Cancer Res.26, 2255–2258 (1966).
—— Brillantes, F. P.: Critical significance of breast structure in the induction of mammary cancer in the rat. Proc. nat. Acad. Sci. (Wash.)45, 1294–1300 (1959).
——— Mammary cancer induced by a single feeding of polynuclear hydrocarbons and its suppression. Nature (Lond.)189, 204–207 (1961).
Jasmin, G., Bois, P.: Coloration différentielle des mastocytes chez le rat. Rev. canad. Biol.20, 773–774 (1961).
— Riopelle, J. L.: Renal adenomas induced by dimethylnitrosamine. Enzyme histochemistry in the rat. Arch. Path.85, 298–305 (1968).
—— Nephroblastomas induced in ovariectomized rats by dimethylbenzanthracene. Cancer Res. 30, 321–326 (1970).
Kovacs, K.: Effect of androgenisation on the development of mammary tumors in rats induced by the oral administration of 9, 10-dimethy1-1, 2-benzanthracene. Brit. J. Cancer14, 531–537 (1965).
Luft, J. H.: Improvements in epoxy resin embedding methods. J. biophys. biochem. Cytol.9, 409–414 (1961).
Movat, H. Z., Fernando, N.V. P.: The fine structure of the terminal vascular bed. IV. The venules and their perivascular cells, pericytes, adventitial cells. Exp. molec. Path.3, 98–114 (1964).
Reynolds, E. S.: The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J. Cell Biol.17, 208–215 (1963).
Riley, J. F.: Mast cells, co-carcinogenesis and anti-carcinogenesis in the skin of mice. Experientia (Basel)24, 1237 (1968).
Watson, M. L.: Staining of tissue sections for electron microscopy with heavy metals. J. biophys. biochem. Cytol.4, 475–485 (1958).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Jasmin, G., Riopelle, J.L. Tumeur du pavillon de l’oreille induite chez le rat par le diméthylbenzanthracène. Virchows Arch. Abt. B Zellpath. 10, 30–39 (1972). https://doi.org/10.1007/BF02899713
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02899713