364 



Tumors. 



from passive congestion, or a nodular h£emorrhagic focus, rather 

 than of a neoplasm. In man, however, such foci have been ob- 

 served in congenital occurrences ; and Ribbert suspects as the fun- 

 damental cause some developmental disturbances of the affected 

 part of the liver. 



The name lymphangioma, or lymph vessel tumor, is applied to 

 congenital tumors in man, which occur as independent bunches of 

 lymph vessels (that is, not in direct relation with the lymph vessels 



Fig. 101. 



Cavernou.s angioma : 0, lacuna filled with blood ; h, indurated intervascular 



connective tissue. 



of the adjacent tissues). They are especially seen in the neck, in 

 the mesentery, the lips and the genital organs, sometimes not well 

 defined and causing rather a diffuse swelling of the part. They are 

 made up of channel-like, anastomosing, multiloculated passages 

 filled with lymph, their walls of fibrous tissue lined with endothe- 

 lium. 



There is only one definite and certain record of the occurrence 

 of tliis type of tumor in animals, published by H. Markus ;* on the 



* Monatsheft f. pr. Tierlieilk. Stuttgart, 1902, p. 185. 



