334 



TUMORS. 



180), consists largely of a series of intercommunicating, irregular-shaped 

 larger and smaller blood spaces lined with eudothelium, and surrounded 

 by a variable quantity of nbrillar connective tissue, which may contain 

 smooth muscle cells. They resemble the erectile tissue of the corpora 

 cavernosa of the penis and clitoris. They are apparently formed by a 

 dilatation of old and new-formed capillaries and veins. They are some- 

 times erectile and sometimes pulsating, and are not infrequently multi- 

 ple. They may be seated in the skin and subcutaneous tissue forming 

 the so-called projecting naevi, or in internal organs. They are often 



FIG. 181. CONGENITAL LTMPHANGIOMA FROM ARM OF CHILD. 



found in the liver and less frequently in bone, the brain, spleen, uterus, 

 kidney, intestines, bladder, and muscles. They are usually of little sig- 

 nificance, though they may give rise to hemorrhages. 



II. Lymphangioma. These tumors consist of dilated lymph channels, 

 which either preserve approximately the general shape of the original 

 lymph -vessels, or are distinctly cavernous in character (Fig. 181) or even 

 cystic. They probably originate in part in new-formed, in part in old 

 lymph channels. A strict distinction between tumors formed by a dila- 

 tation of pre-formed and new-formed lymph channels is not possible, 

 owing to the very primitive character of some of the ultimate lymph 

 spaces and our lack of knowledge of their exact relations to adjacent 

 parts. 



In the lymphangiomata there may be much or little connective tissue 

 between the dilated channels, which are usually filled with a translucent 

 or milky fluid resembling normal lymph. These tumors are usually con- 

 genital, but are sometimes acquired. They usually occur in the skin as 

 soft, sometimes considerably, sometimes but slightly elevated growths, 

 and may occur in the tongue some forms of so-called macroglossia. 

 They are benign tumors, but may rupture, giving rise to serious lym- 

 phorrhosa. 



