PATHOLOGICAL ANATOMY OF THE TESTICLE 487 



is in doubt. Latent twin ova, early and late blastomeres, aberrant primor- 

 dial differentiated tissues, and germ cells, either of the adult testis or 

 aberrantly placed, developing parthenogenetically, have been suggested. 

 The theory of Bibbert ( b ) that all testicular tumors are teratomata, in most 

 of which all tissues but one have been suppressed, is generally considered 

 too radical. 



Tumors of Adult Tissue 



Histoid Tumors. Tumors composed of one type of cell, showing no 

 differentiation into organ-like structures. 



Histoid Tumors Peculiar to the Testicle. (a) Seminoma. These tu- 

 mors are the ordinary carcinomata or epitheliomata, the commonest tumors 

 of the testicle. They are made up of cells having large nuclei, scanty, 



Fig. 7. Seminoma. The section shows the size and character of the nuclei, the 

 shape and clearness of the cytoplasm, and the round cell infiltration. X 330. (Brady 

 Urological Institute collection.) 



delicate protoplasm, and arranged in large alveolar masses. The stroma 

 may be scanty or profuse, and often shows round cell infiltration. The 

 connective tissue reaction may be more abundant than in tumors of other 

 organs. Transition stages are described between these cells and those of 

 the seminal epithelium, from which they are considered to arise. The 

 entire testis is destroyed by the tumor, except occasionally small bits per- 

 sisting around the periphery. This tumor is malignant, metastasizing 

 fairly early to the regional glands. The seminoma was formerly thought 

 to be a sarcoma, but its epithelial nature is now generally admitted. 



