294 



VETERINARY PATHOLOGY. 



endotheliomata as it has been thought by some that the endothe- 

 lium is the only neoplastic portion of an angioma. 



This group is composed of (1) hemangiomata. (2) lymphan- 

 gicuiiata. 



Hemangiomata are blood-vessel tumors. In the human they 

 are found most frecjuently in the skin and may occur in the skin 

 in domestic animals, but are not often observed there because 

 of the pigmentation of the skin. They are found most frequently 

 in the liver and the spleen of the o.x, dog. horse and sheep. An 

 occasional case is observed in the subcutaneous tissue of the 

 horse. HemangicMuata mav be subdivided into four varieties. 



Ilcmangioiua simpler (Capillary telangiectases, nevus, birth 

 mark) is a tumor in which there is an excess of capillary vessels 

 are considerably enlarged or dilated. The vessel wall is usu- 

 ally altered in structure, the endothelial cells being larger and 

 the perivascular tissue more dense. These are quite common 

 m the liver of the o.x where thev appear as irregular blood spots, 

 r.'fl (ir purplish in color. 



Lararf cajtillar 



Lai'cnioiis liciiiinu/iiniiu (hcmanginma cavernosum ) is a tumor 

 composed of spongy tissue similar to erectile tissue. The caver- 

 nous spaces are filled with blood, thus coloring the tumor red or 

 bluish-red. These tumors are found most frequentlv in the liver 

 and spleen. An ox li\-er containing cavernous spaces, each as 

 large as a hen's egg and containing ])arietal thrombi, has been 

 ojjserved. ,-\ lobulated enlargement in the spleen of a dng \^'as 



