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Scientific Proceedings (30). 



7 (345) 

 Multiple tumors in mice. 

 By J. W. JOBLING. 



\^From the Rockefeller Institute for Medical Research^ 



During about two years we have obtained twenty-six mice with 

 spontaneously developed tumors. Of the twenty-six mice, five 

 showed two or more tumors of different types. 



In two, the superficial and larger tumor of the two was situated 

 on the chest wall ; they were spindle cell sarcoma. 



In one, in addition to the sarcoma, both ovaries were much en- 

 larged by papillary cyst-adenomata. The other mouse with the 

 sarcoma showed a 3 mm. wedge-shaped mass in the left lung 

 which was not a metastasis, but a papillary cyst-adenoma. 



In three other mice, the large superficial tumors were adeno- 

 carcinoma and the primary lung tumors, cyst-adenomata. It might 

 be supposed that the lung tumors were metastases, but a study of 

 sections showed great differences between the superficial and lung 

 grow;ths. Metatases show, as a rule, many mitotic figures, while 

 the tumor of the lung, regarded as primary, show karyokinesis ex- 

 ceptionally. Next, the type of cell in the matastases corresponds 

 with that of the primary tumor, besides which the cells are usually 

 packed so closely that the cell outlines are lost, while other differ- 

 ences in protoplasm and nuclei occur. Again, there is little stroma 

 in metastases, unless acini are present, in which case they are easily 

 distinguished, while in the primary papillary growths there is a 

 definite supporting framework. And finally, metastases tend to be 

 invasive, while primary growths do not. The last statement is 

 based on the point noticed that in every instance the primary 

 growth projected from the surface and there was atelectasis of the 

 surrounding tissue, while in metastasic nodules the growth can 

 usually be seen extending into the alveoli without compressing the 

 lung, or else it is confined to blood vessels. These primary lung 

 tumors correspond very closely with those described by Tyzzer. 



