522 THE CHEMISTRY OF TUMORS 



semble in composition sebaceous material, which is characterized by 

 containing a large proportion of cholesterol partly combined with fatty 

 acids. Dermoids sometimes contain masses of fattj' concretions which 

 seem not to depend on chemical changes but on the presence of forma- 

 tive nuclei and framework of desquamated epithelium; they consist of 

 a mixture of neutral fats and cholesterol esters, with some free cho- 

 lesterol.^ Cholesteatomas, in addition to their abundant cholesterol 

 content, contain keratin.'' 



{g) "Butter" Cysts." — In the mammary gland retention cysts 

 form, filled with products of alteration of the milk, including butyric 

 acid and lactose (Klotz),® and these are called "butter cysts" or 

 milk cysts. Analysis of the contents of such a cyst by Smita^ gave 

 the following results, as compared with human milk: 



Cyst contents Human milk 



Fat 72.97 3.90 



Casein 4.37 0.63 



Albumin 1.91 1.31 



Milk-sugar 0.88 6.04 



Ash 0.36 0.49 



Water 20.81 87.09 



Fats consisted of — 



Cyst Cows' milk 



Stearin and palmitin 37.0 50.0 



Olein 53.0 42.2 



Butyrin 9.0 7.8 



Occurring independent of lactation usually, but not always, are the 

 ''soap cysts," which contain chiefly calcium and magnesium soaps, 

 but also neutral fats, free fatty acids, and traces of cholesterol 

 (Freund).8 



(2) Malignant Tumors 



The chief general features of the composition of these growths 

 have been considered in the discussion of the chemistry of tumors 

 in general. A malignant tumor differs from a similar benign tumor 

 chiefly in having usually a larger proportion of the primary cell con- 

 stituents, and a smaller proportion of the secondary constituents and 

 intercellular substances, since these are largely the product of the 

 functional activity of the cells, which, in malignant tumors, do not 

 often develop sufficiently to functionate extensively. Hence malig- 

 nant tumors usually show a rather high proportion of the characteristic 

 constituents of nucleoprotoins; /. e., phospiiorus and iron. If rapidly 



'Lippert, Frankf. Zeit. Path., 1913 (14), 477. 



^Risel, Verh. Deut. Path. Gesell, 1909 (13), 322. 



'■An "oil cyst" behind the ear has been fully analyzed by Kreis (Schweiz. 

 Apoth. Ztg., 1918 (56), 81) and found to contain, in addition to much neutral 

 fat and cholesterol, consideral)le amounts of high unsaturated hydrocarbons. 



* Arch. klin. Chir., 1880 (25), 49. 



' Wien. klin. Woch., 1890 (3), 551; see also Zdarek, Zeit. phvsiol. Chem., 

 1908 (57) 461. 



« Virchow's Arch., 1899 (156), 151. 



