i86 APPLIED ANATOMY. 



years. They are not in any way dangerous. They are composed of a number of 

 dilated acini. Another form is degenerative in character, occurring in the decline of 

 life, and consists of a large number of various sized, usually small, cysts located 

 mostly toward the deep surface of the gland. They contain mucoid and degenerated 

 material produced by the lining membrane of the acini. The whole breast is apt to 

 be studded with small shot-like cysts and both breasts are usually involved. This 

 affection in itself is not malignant, but it may become so by intracanalicular growths 

 springing up from the walls of the cysts. 



Adenomatous growths are encapsulated, usually single, and are composed of 

 three distinct elements. These are glandular tissue more or less normal in character, 

 glandular tissue cystic in character, and fibrous tissue. The fibrous tissue forms the 

 capsule as well as the stroma in the meshes of which latter glandular tissue, nearly 

 normal, occurs. These are called Jibro-adenomata and if the glandular tissue is 

 quite abundant they may be called adenomata. If the glandular acini are dilated 

 so as to overshadow the fibrous portion, then it is called a cystic adenoma. These 

 cystic growths may be quite large. 



Malignant Tumors. The malignant growths of the breast are either sarco- 

 mata or carcinomata. 



Sarcomata originate from the fibrous stroma of the breast surrounding the ducts 

 and acini. As it increases in size it may irritate the glandular structure and obstruct 

 the ducts, thus forming cysts which may be quite large. Such a growth has been 

 called a cystic sarcoma. It also shows itself as a single tumor, which may be large 

 but solid. The lymph-nodes are rarely affected. The disease when it wanders 

 from the seat of the primary growth shows itself in some of the internal organs. It 

 is disseminated by the blood and not by the lymphatics. 



Carcinomata originate from the epithelium lining the ducts and acini. For our 

 purposes we may divide them into two classes, those that grow into the ducts (intra- 

 canalicular} and those that break through the ducts and invade the surrounding 

 tissues, of these scirrhus is the type. 



Intracanalicular growths have by many authors been considered nonmalignant on 

 account of the rarity of their producing general infection. They grow at times rapidly 

 and produce tumors of considerable size. On section they contain many cysts and 

 into these cysts, which are derived from the dilated milk-ducts, protrude outgrowths 

 from the walls. Sometimes the cavity of the cyst has its liquid contents replaced by 

 the solid tumor which has grown into it. A discharge of bloody serum from the 

 nipple is common in these growths. 



Scirrhus is the ordinary form of cancer of the breast. It starts in the epithelial 

 structures of the gland, breaks through the basement membrane and involves the 

 structures immediately adjacent to it, and is disseminated more widely by the lym- 

 phatics. Pagef s disease is a true carcinoma which begins as an eczema or ulceration 

 around the nipple and later becomes disseminated. 



Carcinoma follows the gland structure, and readily involves the pectoral fascia 

 covering the pectoralis major muscle. Anteriorly, the gland structure in places 

 follows the ligaments of Cooper to the skin above, hence the frequency with which 

 the skin is involved. 



The scirrhus variety does not involve the ducts in the same manner as does the 

 intracanalicular variety, hence bloody discharges from the nipple are not so common 

 as in that affection. The disease, when affecting the region of the nipple, has been 

 considered more dangerous because of the greater development of the lymphatics, 

 particularly the subareolar plexus of Sappey, at that point. 



Carcinomatous disease extends especially by way of the lymphatics. These 

 follow the fibrous and canalicular structure, therefore on section the cancerous tissue 

 can be seen extending like roots into the surrounding gland. This tissue shrinks, 

 contracts, and becomes harder as the disease progresses, that is why retraction of the 

 nipple and dimpling of the skin occurs. The most free lymphatic drainage occurs 

 toward the axilla, not toward the mediastinal nodes. The first nodes to show infec- 

 tion are those lying along the edge of the pectoralis major muscle about the level of 

 the third rib. Later, the nodes at the anterior edge of the scapula accompanying the 

 subscapular artery become involved, or those along the axillary vessels. Still later 



