TUMORS. 283 



which the cell processes are apparently continuous with the pro- 

 cesses of adjacent cells. Myxoma cells have an oval nucleus and 

 the spaces between the cells and cell processes are filled with 

 mucus, which appears as a stringy, gray substances that stains 

 red with eosin. Myxomatous cells produce both kinds of fibres, 

 i. e., glia and collagen fibres. Tl^e collagen fibres are more or 

 less separated from each other by a varying quantity of fluid 

 containing mucin. Myxomata are prone to degeneration, result- 

 ing in the formation of a cyst, or the fibrous capsule may become 

 eroded, allowing the degenerated contents to escape into the sur- 

 rounding tissue or upon a surface. In the latter case the degen- 

 erated contents is usually absorbed. Cicatricial tissue is usually 

 produced in the cavity or space occupied by the myxoma. Sub- 

 surface, myxomatous, degenerated areas may become infected, 

 resulting in abscess formation. 



Clinically, myxomata are benign tumors. They grow slowly 

 by interstitial expansion, do not recur when removed, and ex- 

 tend only by continuity or contiguity. 



These tumors are differentiated from mucoid degeneration, as 

 the latter contains no stellate cells, and there are usually some 

 of the cells present in mucoid degeneration that are normally 

 present in that area. Clinically, it may at times be difficult to 

 distinguish between mucus retention cysts and myxoma, but by 

 the exploring needle the contents of the cyst may be evacuated 

 and thus the nature of the mass will be determined. 





CHONDROMA 



A chondroma is a cartilaginous tumor. They occur in cattle, 

 sheep, dogs, horses and fowls. They are found most frequently 

 in the location in which cartilage is normally found. The ster- 

 num seems to be a favorite location for their development, prob- 

 ably because of the frequent injuries of the sternal cartilage due 

 to the fracture of ribs and other injuries. They not infrequently 

 occur in other bones, possibly developing from islands of cartil- 

 age that have not ossified, or from marrow or periosteum. They 

 also occur in glandular tissue as the thyroid, parotid, ovary and 

 testicle, and a few cases of chondromata of the lung have been 

 reported. 



These tumors appear as hard, nodular, well-defined growths, 

 unless they are undergoing degeneration. In this case they may 

 be of the nature of cysts, or if their capsule is ruptured, they may 

 be soft, spongy, diffuse masses. They are variable in size. A 

 chondroma weighing 12 kilograms (26 1/5 lbs.) was obtained 



