524 THE DIGESTIVE SYSTEM. 



membrane. These masses soon degenerate, soften, and form ragged 

 ulcers. 



Syphilitic Stomatitis. As a result of syphilis there may be produced 

 either the so-called mucous patches or gummy tumors. In the mucous 

 patches the epithelial layer is at first thickened and the papillae of the 

 stroma are swollen and infiltrated with cells (see Fig. 128, page 257 and 

 Fig. 129, page 258). This may be followed by desquamation of the 

 epithelium and ulceration. 



TUMORS. 



Fibroma, lipoma, and enchondroma have been seen in a few cases in the 

 lips. When they appear in the mouth they usually grow from the bones. 



Papilloma occurs most frequently at the edges of the lips, but is 

 also found on the gums, the floor of the mouth, and the cheeks. They 

 are formed of hypertrophied papillae, covered with thickened epidermis. 

 They often ulcerate. Angioma, either congenital or developed after birth, 

 occurs in the lips. Adenoma may be formed in the mucous membrane 

 covering the mouth, lips, and soft palate. The tumors are rounded, 

 usually small, sometimes as large as a hen's egg. They may be situated 

 in the thickness of the mucous membrane, or project in a polypoid form. 



Carcinoma is of frequent occurrence and is usually of the epithelioma- 

 tous form. Such tumors may form at any part of the mucous membrane 

 of the mouth, but often begin in the edge of the lower lip as a result of 

 persistent irritation, as in pipe smokers. 



They may originate in an ulcerating papilloma, or as a flat, super- 

 ficial growth from the deeper layers of the epithelium, or as deep nod- 

 ules starting in the mucous glands. They are composed of large masses 

 of epithelial cells, closely packed together, often forming nests, and 

 arranged in anastomosing tubular masses. The stroma surrounding 

 these masses is infiltrated with cells. In a few cases the infiltration of 

 the stroma with small round cells may be very marked, so marked that 

 the epithelial growth may be obscured. The new growth may increase 

 in size, ulcerate, infiltrate the adjacent tissues, and may give rise to 

 metastatic tumors. 



Cysts. Dermoid cysts and cysts of the embryonal branchial clefts 

 may involve the mouth. Simple cysts may form in the jaws from aber- 

 raucies in the development of the teeth. For a description of the so- 

 called adamantinoma see page 349. 



The Tongue. 



Malformations. 



Absence of the tongue may be associated with the extreme defects of development 

 of the face already mentioned. 



The anterior portion of the tongue may be absent while its base remains. The 

 lower jaw is then small. 



The tongue may be partly or completely adherent to the floor of the mouth. The 



