Vascular liver tumors induced in Mastomys (Praomys) natalensis by single or twofold administration of dimethylnitrosamine
Wayss, K.; Bannasch, P.; Mattern, J.; Volm, M.
Journal of the National Cancer Institute 62(5): 1199-1207
1979
ISSN/ISBN: 0027-8874 PMID: 286097 Document Number: 141902
Administration of dimethylnitrosamine (DMNA) to M. (P.) natalensis made it possible to induce vascular tumors of the liver and follow all stages of tumor development. At the age of 5 wk, male and female animals received 10 mg DMNA/kg body wt once or 5 mg DMNA/kg body wt twice, injected i.p. (dose/animal: .apprxeq. 0.35 mg in males and .apprxeq. 0.25 mg in females). They were killed 35, 41, 47 and 55 wk after application of the carcinogen. Of 173 experimental animals, 164 (95%) developed benign hemangloendotheliomas and 10 also developed malignant hemangloendotheliomas. The benign hemangloendotheliomas were characterized by solitary or multiple distended blood lacunae. Macroscopically, they resembled pellosis hepatis. The distended blood lacunae were frequently thrombosed. The coating endothelium appeared only slightly altered (inconstant nuclear enlargement) under the light microscope. Focal sinus dilatations were regarded as early stages of these tumors. In advanced stages, entire liver lobes could be interspersed by a diffuse hemangloendotheliomatosis. Tumor formations were occasionally found that resembled the cavernous hemangioma in man. Rupture of the hemangloendotheliomas often gave rise to hemorrhaging into the abdominal cavity. In contrast to the benign hemangloendotheliomas, the hemanglosarcomas, which appeared in later stages of the experiments, showed a pronounced proliferation of atypical sinus wall cells with pronounced polymorphism of cells and nuclei. In isolated cases, the sarcomas metastasized into the lungs and adrenal cortex. Most hemanglosarcomas were close to benign hemangloendotheliomas. The possibility of a transition from benign to malignant hemangloendotheliomas was examined.