CAVERNOUS TUMOURS. 



167 



Cavernous tumours are occasionally malignant ; but their 

 malignity usually depends on a manifest complication with 

 melanotic sarcoma, whose nodular foci are develoj^ed in the tra- 

 beculae of the cavernous tumour. 



§ 132. Cavernous metamorphosis of fibrous sarcoma itself is 

 peculiarly interesting. Billroth was the first to speak of a ^' ca- 

 vernous fibroid." I have already remarked, when speaking of 

 the spindle-cell variety of sarcoma, that its vessels had as good 

 as no proper walls, and therefore remained gaping on its cut 

 surface. The same is true of the fibromata. Fibromata witli 

 exceptionally wide and gaping vessels may even appear quite 

 spongy. Billroth found that naso-pharyngeal polvpi, whose 



Fig. 55. 



3» o,^-^ ooo 





Cavernous fibroid, after Billroth. 

 polypus.) 



(Xaso-pliaryngeaT 



growth is peripheric, are especially prone to exhibit a cavernous 

 habitus; and I can assert, from independent observation, that 

 the cavernous tissue in such cases originates in i)recisely 

 the same way as that which I have just described. Fig. 55 

 represents a vertical section through the circumference of a 

 cavernous fibroid. Externally, we have a very vascular embry- 

 onic tissue ; internally, the familiar trabeculas of the cavernous 

 tissue ; while between the two are seen the transitional phases. 

 I have placed cavernous tumours under fibromata on account of 

 the identity of the histological processes which underlie the 

 development of both ; should any one doubt the adequacy of 



