and Laboratory Methods. 1469 



and of the vasa vasorum. The pecuHar feature was the proUferation of the 

 endotheUal cells in these spaces. The writer regards the process as a primary 

 endothelioma, although he admits that it may be simply the result of chronic 

 inflammation. There is an excellent resume of the literature of endothelioma. 



J. H. p. 



MacCallum, W. G. On the Intravascular MacCallum Studied a malignant tumor, 

 Growth of Certain Endotheliomata. Con- . . ^. • ^i i r. . .• i i,- i t,„ 



tributions to the Science of Medicine, dedi- ongmatmg m the left testicle, which he 



cated by his pupils to Dr. W. H. Welch, designates lymphendothelioma testis, 

 imore, pp. 497-509, 1900. ^j^^ primary tumor formed a nodulated 



mass about 6x5 cm. in size. It was succulent, myxomatous in places 

 and variegated in color by opaque yellow areas of necrotic tissue. Death 

 occurred four months after the removal of the testicle. The growth 

 had extended from the scrotum in a remarkable manner. The spermatic 

 vein was packed with a somewhat cylindrical tumor mass which extended 

 upward through the left renal vein into the vena cava, in which it spread 

 out into a bunch of translucent villus-like processes which extended throughout 

 the whole length of the vena cava and projected into the right auricle. These 

 curious formations resembled the villi of hydatidiform moles. Similar bundles 

 were also found in the pulmonary arteries and in the pulmonary, jugular and 

 subclavian veins. The lungs, liver, intestine and brain contained tumor nodules 

 and there were local recurrences in the scrotum and groin which formed a chain 

 leading up to a large tumor mass in the lumbar region. The tumor nodules in 

 the lungs and liver were rounded and rather sharply outlined ; many were semi- 

 translucent and appeared to be made up of small cysts, others were more opaque 

 and consisted of very soft, succulent, whitish tissue. 



Histologically the neoplasm consisted of a framework of soft myxomatous 

 tissue which contained cysts and tubules of various sizes and shapes. These 

 spaces were lined with cells which varied in height from a flat, scale-like form, 

 exactly resembling the endothelium of the lymphatics, through all gradations to 

 high columnar epithelium-like cells. In places the cells were piled up two or 

 three rows deep and arranged in folds and papillary masses which had invaded 

 the surrounding tissue and finally had broken their way into the veins. The 

 intravascular growths were covered by the endothelium of the veins, just as an 

 organizing thrombus would be covered, and continuing in their development 

 they formed papillary masses which projected along the lumen of the vein and 

 occasionally formed secondary attachments to the walls. Passing through the 

 heart into the pulmonary arteries, these masses became attached to the walls of 

 the finest arterioles, and breaking through these gave rise to the secondary 

 tumor nodules in the lung. The nodules in the liver, brain, and intestine were 

 probably tertiary in origin. 



The cyst-like spaces found in the metastases and intravascular masses, as 

 well as in the primary tumor, were lined by cells which do resemble epithelial 

 cells and have been regarded as epithelial in nature by the few other investi- 

 gators who have studied this type of tumor. MacCallum, however, in view of 

 the facts — (a) that no connection with the well defined epithelium of the seminal 



