TUMORS. 



337 



the adenomata and carciuomata, where conformity to the glandular type 

 merges into the lawlessness of growth characteristic of carcinomata. In 

 this border region a certain degree of individual bias must be permitted 

 in assigning a name to the new growth. In some cases a sharp distinc- 

 tion cannot be made ; or the tumor may share in the characteristics of 

 both, and then we very properly make use of the term adeno-carcinoma 

 or carcino-adenoma. 



I. ADENOMA. 



The structure of the cellular elements of these tumors, and their ar- 

 rangement into acini and ducts, vary even more than do those of the 

 normal glands whose types they follow. The acini usually possess a 

 more or less well-defined lumen and membraua propria (see Fig. 183). 

 The adenomata sometimes merge into the surrounding tissue, or are con- 

 tinuous with the gland tissue in which they originate ; sometimes they 

 are distinct in outline and encapsulated. The interstitial tissue is some- 

 times abundant, sometimes sparse, and may contain few or many cells. 

 The irregularities of their growth often lead to the stoppage of the 



FIG. 184. ADENOMA OF STOMACH. 

 A form of tumor which is on the border line of carcinoma and might be called adeno-carcinoma. 



lumina of their ducts and the formation of cysts. They may undergo 

 mucous metamorphosis and may become sarcoinatous. 



Adenomata occur in the mamma, ovary, liver, kidney, thyroid, sali- 

 vary and lachrymal glands, and in the caruncle ; in the mucous mem- 

 brane of the nose, pharynx, stomach, intestine, and uterus; and occa- 

 sionally in the sebaceous and sweat glands of the skin. The so-called 

 multilocular cystomata of the ovary are among the most important of the 

 adenomata. 



There are numerous papillary and polypoid growths, in gland ducts 

 and on mucous membranes, in which there is an actual new formation 

 of gland epithelium ; but this is usually secondary to a primary growth, 

 beneath the epithelial layer, of some other tissue, such as fibrous or 



