SPONTANEOUS NEOPLASMS IN MICE 



229 



both sexes. The only other cases in the Uterature are a papillary adenoma 

 of the ependyma cells of the lateral ventricle, an endothelioma of the cere- 

 brum and an adenoma of the hypophysis in 11,118 autopsies by Slye (60). 

 One other adenoma of the hypophysis has been reported (19). In our stocks 

 we have diagnosed two adenocarcinomas of the hypophysis composed chiefly 



Normal brain 



— Medulloblastoma 



Fig. 126. — Medulloblastoma from the brain of a mouse (X200). 



of eosinophile cells. These were in hybrids from a cross between the C57 

 black and C57 brown stocks. 



Other Rare Sites of Tumors 



Among the rare sites of tumors is the heart. We have observed a 

 rhabdomyosarcoma of this organ and Hertzog (25) reported a papillary 

 fibroma of the cardiac valve. Slye (59) reported tumors of the thyroid. 

 However, we have not observed neoplasms at this site. In the glands 

 around the eye we have found two papillary cystadenomas, a papillary 

 adenocarcinoma and an adenocarcinoma. 



This chapter has been intended to emphasize, mainly, the types of 

 spontaneous tumors that are most commonly encountered. As data on 



