Correlation of Gross Structure and Microstructure with Clinical Features
'.
..
~
...
., .'
....... \ .\
..
-,
.
.-.<.-, t
." ; '" .... I,,f,:â&#x20AC;˘
.
â&#x20AC;˘ ,r
. '"
..
19
..'
.'
-~
,-
.
CHAPTER J
-.
-.
.\
Fig. 3-3. Light pink region of oral mucosa. Photomicrograph of mucosa taken from the hard palate. The generous keratin layer (I) is combined with the dense fibrous and quite avascular lamina propria (2). This combination accounts for the lighter coloration seen clinically on the hard palate and attached gingivae.
histologic study whether the color is induced by melanin, hemosiderin, heavy metals, or pools of clear fluid. Surfaces ormal mucosa is smooth and glistening except for the area of the rugae and the attached gingiva, which frequently demonstrates stippling and pebbling. The surface of a pathologic mass may be smooth, papillomatous, ulcerated, eroded, keratinized, necrotic, or bosselated. Masses that arise in tissues beneath the stratified squamous lining are, almost without exception, smooth surfaced. They may originate from mesenchyme, the salivary glands, an abscess, or an embryonic rest. As the nest of cells enlarges below and presses against the stratified squamous epithelium, the epithelium responds by a combination of stret\hing and minimal mitotic activity. Therefore, as the mass becomes larger and bulges into the oral cavity, it is covered with a smooth epithelial surface. Examples of such masses are fibromas, osteomas, chondromas, hemangiomas, intradermal and compound nevi, many of the minor salivary gland tumors, cysts, retention phenomena, lipomas, myomas, schwannomas, neurofibromas, space abscesses, subepithelial bullae of erythema multiforme, bullous lichen planus, and bullous pemphigoid (Fig. 3-5). Even the malignant counterparts of such tumors often have smooth surfaces, especially in their early phases, but when these bulging lesions are situated in a region subjected to repeated trauma, their smooth surfaces become ulcerated and necrotic.
Fig. 3-4. This clinical picture illustrates the darker color of vestibular mucosa as contrasted with the lighter color of the attached gingivae. The histologic difference between the two regions explains these color differences.
Some exceptions to this rule are the intraepithelial vesicles and blebs seen in herpetic lesions and pemphigus. They are smooth despite the fact that they originate in the surface epithelium. As a rule, however, masses that originate ill the stratified squamous epithelium almost invariably have corrugated or papillomatous sUifaces. Examples of these are papillomas, verrucae vulgari (warts), sebolTheic keratoses, keratoacanthomas, verrucous carcinomas, and exophytic and ulcerative squamous cell carcinomas (Fig. 3-6). Exceptions would be the less than rough but pebbly surfaces