TUMORS. 531 



an adeno -myeloma, which is often combined with cystic forma- 

 tions, and this condition was called cysto-sarcoma mammce. In such 

 tumors, well-marked cauliflower-like vegetations protrude into the 

 calibers of the newly formed dilated and folded glandular spaces. 

 These vegetations were erroneously supposed to be intraglandular ; 

 but they are obviously produced by an outgrowth of the connect- 

 ive, tissue lying behind the glandular wall, which is usually ex- 

 tremely vascular, and pushes and folds the wall into peculiarly 

 complicated prolongations. Adeno-myeloma of the breast some- 

 times breaks open and ulcerates, and the vascularized vegetations 

 may bulge out from the ulcer, with a simultaneous rapid growth 

 of the tumor. Nevertheless, this variety of tumor is known to 

 be comparatively benign, and to admit of a permanent cure by 

 extirpation. 



In the thyroid body adenoma often occurs, producing the 

 disease termed goitre. Either the alveoli, containing lymph-cor- 

 puscles and colloid material, are uniformly dilated the so-called 

 parenchymatous goitre or some of the alveoli, still lined by 

 the original embryonal epithelia, may become cystic and, in addi- 

 tion, be provided with numerous vascularized vegetations on the 

 inner surface of the cyst cystic goitre. From the alveoli can- 

 cer may also develop as a primary or secondary tumor. 



The majority of cysts are secondary formations of adenoma. 

 We sometimes observe cystic spaces in polypoid tumors, and can 

 trace the gradual transformation of the glandular epithelia into 

 a mucous, colloid, or serous mass. As an intervening stage, a 

 sort of myxomatous tissue is observed -arising from medullary 

 corpuscles, into which the epithelia change before their liquefac- 

 tion. The closed cavity of the original alveolus is gradually dis- 

 tended and becomes a cyst, the inside wall of which is lined by 

 flat epithelia. (See Fig. 220.) 



The sebaceous cysts and milium in the skin are invariably pre- 

 ceded by a stage of adenoma. In the subcutaneous tissue other 

 cysts may arise independently of epithelial growth f. i., the 

 meUceris, a cyst with honey-like contents ; the hygromata, cysts of 

 the bursce mucosw; and the so-called ganglia, cysts of the sheaths 

 of tendons. The cause of the appearance of cysts in such cases 

 as these is not known. Obviously, the cystic formations which 

 spring from an accumulation of blood, due to an extravasation, 

 cannot be considered as tumors in the strictest sense of the word. 



Unquestionably, epithelial growth produces the so-called der- 

 moid cysts, which are very probably caused by anomalous forma- 



