294 PATHOLOGY OF NUTRITION. 



as in the skin, lungs, meninges, testicle, and parotid gland. If 

 occurring as an outgrowth from bone, they are known as ex- 

 ostoses (Fig. 122). 



Angeioma, 



An angeioma is a tumor composed mainly of bloodvessels. 

 There are two varieties simple and cavernous. In simple 

 angeioma, or leleangiectasis, there is an abundant plexus of ar- 

 teries, veins, and capillaries as found in the skin in ncevi. 

 They also occur on mucous surfaces and rarely in the internal 

 organs. 



Cavernous angeioma, which is the more common variety, re- 

 sembles microscopically the tissue of the corpus cavernosum 

 of the penis, being made up of large, irregularly shaped, in- 

 tercommunicating spaces filled with blood, lined by endothe- 

 lium, and separated from each other by connective-tissue par- 

 titions. They are most common in the liver, but are found 

 also in the spleen, kidney, and uterus. 



Lymphangeiomata are formed of dilated lymphatic vessels 

 identical in structure with the hsemangeiomata. Cavernous 

 lymphangeiomata have been occasionally found in the kidneys 

 and lymphatic glands. In congenital enlargement of the 

 tongue macroglossia, and of the lips macrocheilia, and in 

 elephantiasis, there is a diffuse dilatation of lymphatic struct- 

 ures. 



Sarcoma. 



A sarcoma is a richly cellular malignant tumor of the con- 

 nective-tissue group, which, histologically, resembles granula- 

 tion i. e.j embryonic or undeveloped connective tissue. The 

 cells, round and spindle-shaped, are greatly in excess of the 

 intercellular substance. The more cellular its structure the 

 greater the malignancy of the growth. Though the amount 

 of the intercellular substance may be very scant, yet it may 

 be of such quantity and character as to give rise to special 

 varieties fibrosarcoma, myxosarcoma, chondrosarcoma, and 

 osteosarcoma. The bloodvessels, which in some instances are 

 extremely abundant, are simple channels lined with a single 

 layer of cells. 



