Endocardial tumors induced by carbamate or fluorenylacetamide derivatives in rats

Endocardial tumors were induced in 18 rats treated with derivatives of carbamates and in 4 rats treated with derivatives of fluorenylacetamide. The endocardial tumor of 1 rat treated with N,N'-2,7-fluorenylenebisacetamide metastasized to the lung. This is the first report of metastasis of an endocardial tumor. Among the more than 60,000 accessions at the Registry of Experimental Cancers, Division of Cancer Cause and Prevention, National Cancer Institute, there are 4 untreated rats with endocardial tumors. On the basis of the light microscopic morphology, we have classified these endocardial tumors as mesenchymal.