330 CLINICAL CONSIDERATIONS 



discussion of the tumors of the androgenic zone to the next 

 chapter and consider here only those tumors which originate 

 from the medulla and cortex proper. 



TUMORS OF THE MEDULLA 



As we have seen in Chapter II, the adrenal chromaphil 

 tissue is derived from the sympathetic nervous system. The 

 original cell which gives rise to both the sympathetic and 

 chromaphil cells is a small, lymphocyte-like structure known 

 as the sympathogone. From these sympathogonic cells arise 

 the sympathoblasts which in turn give rise to the sympathetic 

 ganglion cells, and the chromophiloblasts (also called phaeo- 

 chromoblasts) which give rise to the chromaphil (or phaeo- 

 crome) cells of the medulla. There are thus five types of 

 embryonic and mature cells to be found in the medulla during 

 its development, as indicated in the following schema: 



Sympathogone 



Sympathoblast Chromaphiloblast 



I I 



Sympathetic ganglion Chromaphil cell of the 



cell adrenal medulla and 



other paraganglia 



The sympathoblasts and chromophiloblasts, which are the 

 intermediate cell forms between the sympathogone and the 

 sympathetic ganglion cells and chromaphil cells, respectively, 

 are morphologically similar. There are thus in reality only 

 four types of cells in the medulla which can be anatomically 

 differentiated. Each of these may give rise to a tumor con- 

 forming to the cell-type from which it is derived. Two of 

 these are immature cell forms: the sympathogone and sym- 

 pathoblast (or chromophiloblast) . The other two are mature 

 forms: the ganglion and paraganglion (or chromaphil) cells. 

 Tumors derived from these cell types are denoted by the names 

 of their cells of origin. The use of the terms glioma, round cell 



