1176 RADIATION BIOLOGY 



in smooth muscle, obliteration of capillaries by proliferation of the endo- 

 thelium, and telangiectasia of other capillaries. The obliterative changes 

 in the veins and arteries were manifested chiefly by a great increase in 

 the connective tissue beneath the endothelium and a marked thickening 

 of the media. Hypertrophy of the epidermis was a constant finding. 

 Complete absence of hair follicles and of sebaceous and coil glands was 

 the rule in lesions of long duration. In no case was there evidence of 

 proliferation of any of the dermal appendages. Coil glands were often 

 found in regions in which there was a total absence of hair follicles and 

 sebaceous glands. 



Saunders and Montgomery (1938) described the characteristic histo- 

 pathological picture of radiodermatitis as follows: The epidermis is 

 hyperkeratotic and acanthotic, and usually there is an associated increase 

 in the stratum granulosum. Necrosis and ulceration of the epidermis are 

 frequently encountered. The formation of abscesses and spaces (Liicken) 

 in the epidermis are seen infrequently. Destruction of the elastic tissues 

 occurs in severe cases. Sometimes a few fine fibers of newly formed 

 elastic tissue can be demonstrated. There is new formation of capil- 

 laries arising from thickened vessels in the upper cutis. The larger 

 vessels show varying degrees of thickening of the adventitia and media 

 and proliferation of the intima to the point of partial or complete occlu- 

 sion. The infiltrate in the cutis is not consistent or characteristic, poly- 

 morphonuclear leukocytes predominating in necrotic connective tissue in 

 areas of ulceration, and lymphocytes predominating elsewhere. The 

 sebaceous glands are almost invariably destroyed. Next, and depending 

 on the severity of the radio 'ermatitis, the hair follicles become involved 

 and, in the case of third-degree injuries, the sweat glands are usually 

 atrophic or completely missing. Hyperpigmentation, a feature of acute 

 radiodermatitis, is not evident, very little melanin being demonstrable 

 microscopically. 



All epitheliomas originated in the epidermis and none in the hair 

 follicles or sweat ducts. Most epitheliomas studied show phenomena of 

 individual cell keratinization ; many showed giant epithelial cells, repre- 

 senting amitotic cell division. Roentgen epitheliomas simulate and even 

 duplicate the histologic picture of epitheliomas arising from senile and 

 arsenic keratoses, and they tend to begin as epitheliomas in situ, with 

 the various phenomena of individual cell keratinization. 



Gamma radiation, from radon seeds, was widely used for the removal 

 of hemangiomas. In a review of all the case histories of a large metro- 

 politan tumor clinic, four cases have been found in which late radiation 

 dermatitis or a skin carcinoma followed in thirteen to sixteen years. Two 

 patients received much larger doses (about 1 10,000 r) than did the radium 

 poisoning cases, yet the tumor development time is comparable (Evans, 

 see Brues, 1951). The tumors so induced arise either in the epidermis or 

 subjacent connective tissue. 



