480 



TUMORS. 



ized. In the latter case they bear the name myxo-angioma. If 

 the covering epithelium is freely supplied with pigment, it estab- 

 lishes the variety called pigmented ncevus ; such tumors may be 

 congenital or they arise in middle life. Sometimes the myxo- 

 matous tissue in this situation is combined with fat, forming 

 myxo-lipoma. 



In mucous membranes myxoma is also common, usually as 

 pediculated, translucent tumors in the mucosa of the nasal, the 

 pharyngeal cavity, the gums, the larynx, the rectum, and the 

 uterus. Often they are combined with glandular new formation, 

 representing the variety termed myxo-adenoma. In the external 

 auditory canal and the tympanum they sometimes have the 



FIG. 181. MYXOMA. PHARYNGEAL POLYPUS. 



.R, delicate fibrous reticulum with nuclei at the points of intersection, inclosing spaces 

 which contain a jelly-like basis-substance and plastids ; P, either nucleated or of the aspect of 

 nuclei ; V, blood-vessel. Magnified 600 diameters. 



appearance of simple granulations, as observed in wounds heal- 

 ing by suppuration; and as both granulations and myxomata 

 are identical in their minute structure, a positive statement as to 

 their etiology is impossible. 



Myxoma also appears along nerves, and many of the tumors 

 termed " neuromata" are myxomatous growths arising from the 



