72 THE UNIVERSITY OF OKLAHOMA 



foreign formation unconnected with the other constituents? (3). 

 How extensive are these tumors throughout the kidney? Are 

 there miliary and sub-miliary foci in whicli the initial stages can 

 he seen? (4). Is this to be interpreted as hyperplasia? 



The usual histological method of serial sections, stained with 

 eosin and hematoxylin was used in carrying out these investigations. 



Conclusions 



1. These tumors apparently arise from glomeruli. The points 

 of similarity between these tumors and glomeruli are as follows: 

 (a) the general shape and appearance is that of a glomerulus; (b) 

 the tumors consist of branching and ataomosing capillaries as 

 seen in a normal glomerulus ; (c) there is a definite capsule 

 around the structure; (d) in some cases there are atypical tubules 

 ])roceeding from the structure which is representative of the proxi- 

 mal convoluted tubule as it leaves a normal glomerulus. The chief 

 I-ioints of difference are the following: (a), the capillaries instead of 

 lireaking up and anastomosing when they first enter the sub-capsu- 

 lar space in some instances follow up the papilla-like structures of 

 connective tissue; (b) the epithelium of the capsule and also the 

 epithelium of the capillaries of the glomerular-like tuft is cuboidal 

 and even cylinderical columnar epithelium instead of simple 

 squamous; (c) the tubules which leave the tumor are atypical in 

 structure. However, this would be expected in the case of tumors. 



2. These tumors do not arise from tubular epithelium as is 

 shown by the fact that there is no arrangement of cells into tubules 

 and also the structure of the cells is unlike that of tubular epithelium. 



3. That these tumors do not arise from foreign "cell rests" of 

 adrenal or other foreign tissue but arise from kidney substance it- 

 self is shown by the following facts: (1) the cells found here are 

 different from those seen in adrenal tissue ; (2) the arrangement of 

 the cells differs from that of other foreign tissue; (3) the cells and 

 arrangement of this tumor differ from cells of tumors reported in 

 the literature studied; (4) the large numl^er present would indicate 

 that these are not cell "rests," as it is hardly probably that hundreds 

 of these cell inclusions would be present in one or both kidneys as 

 was true in this case. 



4. The structure and appearance of these growths prove defi- 

 nitely that they are tumors and not hyperplasia. 



