502 TUMORS. 



myeloma) is not of a very malignant type where bone-tissue is 

 formed, though it is possible for the tumor to change to a more 

 malignant form. Myeloma, with numerous globular or spindle- 

 shaped elements, is, as a rule, deficient in new formation of bone. 

 The tumor the size of a child's head, from which Fig. 201 is taken, 

 for a number of years grew slowly, though steadily, while later 

 it increased rapidly to a fatal termination. 



The combinations of myeloma tissue with other varieties of 

 tissue (lipoma, angioma, myoma, neuroma, and adenoma) will 

 be considered in the articles treating of these tumors. Here I 

 only mention that, according to Virchow, there also exists a 

 combination of cancer with myeloma a view which I, from a 

 large number of observations, can corroborate. 



Alveolar myeloma (Billroth) is of a dubious nature. Most 

 pathologists regard it as cancer, .but it seems more correct to 

 class it among the myelomata j for it shows all the clinical and 

 pathological features of such tumors nay, it appears occasionally 

 as a secondary tumor after primary myeloma. A delicate frame 

 of connective tissue forms the alveoli, which are filled with glob- 

 ular, oblong, or irregular and usually nucleated plastids, very 

 loosely connected with one another so loosely, that in sections 

 the alveoli appear incompletely filled. The plastids never reach 

 the size and the polyhedral shape of epithelia, so characteristic of 

 cancer 5 those nearest to the connective-tissue frame are pear- 

 shaped, being attached to the frame by a slender pedicle. I have 

 seen this variety of tumor in the groin, in the testis, the omentum, 

 and the liver ; in both the last-named positions the tumors were 

 secondary, and that of the liver was of a pronounced melanotic 

 type. Perhaps this tumor represents a transition of myeloma 

 into cancer, a transition which in the opposite way cancer to 

 myeloma is of more common occurrence. (See Fig. 202.) 



Myeloma is a malignant tumor, and any portion of the con- 

 nective tissue of the body may serve as its starting-point. In 

 fact, this tumor has been observed in all parts and all organs of 

 the body, except in horny tissue. Contrary to cancer, it is often 

 a growth of childhood and youth, and may occur at any age. Its 

 malignity is intensified when the constituent elements are small, 

 the blood-vessels abundant, and the basis-substance scanty. The 

 presence of pigment, both in the fibrous and medullary portions 

 of the tumor, greatly increases its malignant character. Not 

 infrequently local irritation, particularly injuries of all kinds, 

 can be traced as the exciting cause of myeloma. 



