SPONTANEOUS NEOPLASMS IN MICE 221 



endothelioma has been seen in the Hver of an A stock female. Fibrosarcomas 

 of the Uver have been observed in several stocks. 



Pancreatic Tumors 



Primary tumors of the pancreas are rare. Adenocarcinoma has been 

 observed in one Mus hactrianus female and in two hybrids of this stock 

 crossed with C57 black. Slye (61) reported two cases in 125,000 autopsies. 



Fig. 120. — Adenoma of the renal tubules (X400). ad., adenoma; n.r.t., normal renal 



tubule. 



Carcinoma of the pancreatic islands has been seen twice in our stocks. 

 Hueper (27) reports another case. Fibrosarcoma also occurs in this gland. 



Tumors of the Uro-genital System 



Kidney and Urinary Bladder Tumors 



The kidney is a fairly frequent site for secondary involvement of tumors 

 of the blood forming and blood destroying tissues. However, primary 

 tumors of this organ are not common. We have had one case of adetioma 

 of the renal tubules (Fig. 120) and one case of papillary cyst adenocarcinoma. 

 Several papillomas of the renal pelvis have occurred (Fig. 121A). A few of 



