THE REPRODUCTIVE ORGANS OF THE FEMALE. 709 



Myxoma. This form of tumor may occur as a circumscribed growth 

 replacing part of the mamma, or it may be developed in the same way 

 as the intracaualicular fibromata. It is not uncommon in these intra- 

 canalicular tumors to find a combination of fibrous, mucous, and sarcom- 

 atous tissue in the same tumor. 



Chondroma is a very rare form of tumor in the mamma. A few cases 

 have been described in which it was combined with carcinoma. 



Adenoma. Tumors composed of glandular acini and ducts surrounded 

 by connective tissue are of frequent occurrence in the mamma (Fig. 



FIG. 466. ADENOMA OF THE MAMMA. 

 Type of acini lined with duct epithelium. 



468). They are either single or multiple, or several may be developed 

 successively in the same breast. They grow, as a rule, at first slowly, 

 afterward more rapidly. Their structure may be further complicated 

 by the dilatation of one or more of the ducts which compose the tumor 

 into cysts, and the ingrowth of connective tissue from the walls of these 

 cysts. This growth is often in papillary form papillary cystadenoma 



FIG. 467. ADENOMA OF THE MAMMA. 

 Type of acini lined with irregular epithelial cell masses. 



(Fig. 469). A case of cystic adenoma with ciliated epithelium has been 

 described. ' 



While preserving the gland type the adenomata present great variation 

 in the form and grouping of the epithelial cells of the ducts and acini, 

 so that here as elsewhere various intermediate forms may be found be- 

 tween adenoma and carcinoma. 2 The new-formed glandular epithelium 

 often presents two types, one in which the cells are fairly distinct and 



,..<!/, Virchow's Arch., Bd. clvi., p. 395, 1899. 

 ' See Cystic hyperplasia, p. 706. 



