370 MORBID ANATOMY OF THE SKIN". 



of the skin with a mucous membrane ; sc. on the lips, prepuce, 

 anus, and vulva. When it occurs elsewhere, it is usually 

 secondary, i.e. it is developed in parts which have been affected 

 for years with some sort of morbid growth, without however 

 exhibiting any of the characters of cancer. Among these are — 



1. Some of the above-described overgrowths of the epidermis 

 and papillary body, those more especially, which exhibit from the 

 first a certain preponderance of the epidermic element, sc. cuta- 

 neous horns, hard warts, papillomata ; this gives the classification 

 we adopted in § 300 a very serious clinical significance. 



2. Hypertrophy and dilatation of hair-sacs and sebaceous 

 glands ; atheromatous cysts. 



3. Cicatrices, especially of the scalp. 



The transition to epithelial cancer, as already stated, is in- 

 augurated by an advance of the epidermic boundary, and con- 

 sequently of the epidermis itself, inwards, towards the connective 

 tissue — an advance Avhich gives the growth a destructive, rodent 

 character. 



§ 314. The following varieties of cutaneous epithelioma are 

 based partly upon the locality, partly upon striking anatomical 

 peculiarities of the growth. 



a. Warty epithelioma. One of the most interesting and 

 frequent complications of the anatomical appearances described 

 in § Wo et seqq. is that with papillary excrescences. The mode 

 of transition from cauliflower vegetations to epithelial cancer has 

 already been described (§ 148). Closely connected with this is 

 the circumstance that at the growing border of an epithelioma, 

 in the zone where the sebaceous glands begin to be enlarged, 

 warts, and even small cauliflower excrescences are not seldom 

 found ; and in this way the boundary-line between epithelium 

 and connective tissue is displaced outwards, inverting the 

 order of that displacement inwards, which occurs at the same 

 time. Moreover papillary excrescences are often produced 

 upon and within the epithelioma itself, the epithelioma being 

 primary and the excrescence secondary. I need hardly say tliat 

 in the production of these papillae the stroma takes a leading 

 part. It would seem however as though the release of the 

 stroma, which follows the degeneration, softening and expulsion 

 of the tap-shaped epithelial protrusions, contributed to change 

 the direction in which the development of the epithelioma takes 



