328 



TUMORS. 



FIG. 



172. NECROGLIA OR "SPIDER" CELLS FROM 

 GLIOMA OF THE BRAIN. 



not sharply outlined against the adjacent normal tissue. They usually 

 occur singly, and are comparatively slow in growth. 



They are frequently associated with other tumor tissue, forming glio- 

 myxoma, glio-sarcoma, etc. Owing to the abundance of thin-walled blood- 

 vessels and the softness of the 

 growth, they are liable to inter- 

 stitial haemorrhages, and may 

 then, when occurring in the 

 brain, readily be mistaken for 

 ordinary apoplectic clots. They 

 are liable to fatty degeneration. 

 They usually occur in the brain, 

 spinal cord, and in the optic and 

 other cerebral nerves. The so- 

 called gliomata of the retina are 

 usually small spheroidal-celled 

 sarcomata. 



Pure gliomata are benign 

 Teased specimen. tumors, though in their most 



common combination with sar- 

 coma they may be very malignant. Their usual situation, however, is 

 such as to make them almost always significant, although technically they 

 are benign tumors. ' 



MYOMA. 



Tumors composed of muscle tissue are of two kinds, following the 

 two normal types of muscle, the non-striated and the striated. 



I. Leiomyoma, Myoma Levicellulare. The characteristic elements of 

 these tumors are fusiform, smooth muscle cells, with elongated or rod- 

 shaped nuclei. These are packed closely together, frequently interlacing 

 and ranning in various directions, and are intermingled with a variable 

 quantity of more or less vascular fibrillar connective tissue (Fig. 173). 

 When, as is not infrequently the case, the connective-tissue elements are 

 present in large amount, the tumor is called fibro -myoma (Fig. 174). It 

 is not always easy in sections to distinguish between these tumors and 

 certain cellular fibromata, but the characteristic shape of the isolated 

 cells and their nuclei, together with their uniformity in size, will usually 

 suffice. These tumors are frequently infiltrated with lime salts, and, 

 owing to their density and lack of blood-vessels, they not infrequently 

 degenerate, forming cysts or becoming gangrenous. They may occur 

 singly or be multiple, are usually of slow growth, may be large or small, 

 and are benign. They may occur wherever smooth muscle tissue exists. 

 They are most frequently found in the uterus, where they are often mui- 



1 Our knowledge of the normal neuroglia is still too meagre to permit us to under- 

 stand very thoroughly this class of tumors, and to separate it as precisely as could be 

 wished from certain of its allies among the abnormal connective-tissue growths. See 

 foot-note, p. 303. 



