TUMORS. 



307 



are exemplified in some of the compound ovarian cysts the so-called 

 ovarian cystomata ; but these are really adenomata. 



4. Congenital Cysts. These are of various forms, and their mode of 

 origin is in most cases but imperfectly understood. Some of them are 

 properly grouped among the teratomata. The so-called dermoid cysts of 

 the subcutaneous tissue (Fig. 144) and ovary are marked examples of 

 this class. Certain congenital cysts of the kidney and other internal 



FIG. 144. DERMOID CYST OF THE SKIN. 



This small cyst beneath the skin above the eyebrow is lined with epithelial cells, in places cuboidal in 

 form but mostly merged into an irregular cell mass. The flbrous-walled cyst contained a clear fluid and a 

 little granular cell detritus. 



organs are conveniently grouped here, although it is quite probable that 

 some of them at least originate during fostal life in one or other of the 

 above-described ways, and hence are not essentially different in nature 

 from some of the cysts of other classes. For the mode of formation of 

 certain cysts of the neck see page 526. ' 



Various Lesions Sometimes Described as Tumors. 



There are certain enlargements of the lymph-nodes which are in reality hyper- 

 plasias, sometimes inflammatory in character and sometimes not, and which are often 

 grouped among the tumors as lymphomata. They are not true tumors, and will be con- 

 sidered under the lesions of the lymph-nodes. In the same group are often classed the 

 enlargements of the lymph-nodes in leukaemia and in other general diseases, which are 

 considered in another part of this book. 



Another group of tumors sometimes called lymphomata are in reality sarcomata, 

 and these will be described under the latter heading. 



There is also a group of nodular new formations, the so-called infective granulomata, 

 which in earlier days were classed among the tumors. These are found in tuberculosis, 

 lupus, leprosy, syphilis, glanders, and actinomycosis. They are, however, inflamma- 

 tory new formations, and, as our knowledge regarding them has increased, many of 

 them have been proven to be inci ted by plant parasites (see section devoted to Infectious 

 Diseases). In the case of syphilis the absolute proof is still lacking. 



1 Consult for consideration of ciliated and other cysts, Hess, Ziegler's Beitr. zur path. 

 Anat., Bd. viii., p. 98, 1890; also Zahn, Virchow's Archiv, Bd. cxliii., p. 170, 1896. For 

 later general bibliography of cysts see Asckoff, Lubarsch and Ostertag's " Ergebnisse, " 

 Jalirg. ii. for 1895, p. 456. 



