SPONTANEOUS NEOPLASMS IN MICE 



199 



Tumors of the Dermis, Subcutaneous and Body Wall Tissues 



Many tumors of the dermis and subcutaneous tissues are not easily 

 separated, and for the purposes of this section no attempt to separate them 

 will be made. Benign and malignant forms are found here. These are 

 representative of the type of tissues normally found in the subcutaneous and 

 body wall region. 





Fig. 107. — Rapidly growing epidermoid carcinoma of the skin ( X::oo). 

 little epithelial pearl formation in contrast to Fig. io6. 



This shows 



Fibroma. — This is a benign tumor, not commonly observed, composed of 

 connective tissue cells. These cells are uniform in size and shape and are 

 distributed throughout the intercellular substance. The tumors are 

 encapsulated and invasion does not occur. Mitotic figures are rare. 



Chondroma. — This is a benign tumor originating from cartilage. The 

 cartilage cells are atypical, larger than normal and arranged in irregular 

 islands. They show a tendency to mucoid degeneration or calcification. 

 Blood vessels may be fairly abundant. Mitoses are rare and a well formed 

 capsule is present. This type of tumor is not common among our stocks. 



