[Histoenzymological characteristics of epithelial cells in oral mucosal lesions and jaw cysts. Diagnostic significance].

An histoenzymological study (including oxidative enzymes, diaphorases, acid and alkaline phosphatases and naphtolesterases) of 41 biopsy and operation specimens revealed interesting factors in the diagnosis of some lesions of the buccal mucosa, and also of cysts and ameloblastomas of the jaw. When compared with normal buccal mucosa and epidermis, the enzymatic activities found in the oral lesions, fell into three different types. In non dysplasic leukoplakia, enzymatic activities were found that were similar to those of the epidermis (high oxidative activities, particularly prominent in basal cells and in the granular layer and esterasic activity beneath the keratinised layer). In lichen planus, some vacuolized or necrotic basal cells occurred which lacked enzymatic activity. In the upper layers, the distribution of the enzymes was irregular. In severe dysplasia and epidermoid carcinoma, numerous variations of oxidative, esterasic and acid phosphatase activities were seen from one cell to another. Among the lesions of the jaws, radicular cysts as well as dentigerous cysts, had low enzymatic activities, similar to those of normal buccal epithelium. The epidermoid cysts (keratocysts), because of their highly differentiated keratinization, like leukoplakia, had the same enzymatic activities as epidermis. The enzymatic activities of common ameloblastoma differed from those of malpighian tissues (low oxidative activities without decreasing gradient). Besides round epithelial nests, the stroma showed a high and widespread alkaline phosphatase activity, which indicated a low degree of odontogenic induction. Thus, this peculiar stromal activity may be useful in differentiating between cystic epidermoid varieties of ameloblastoma and the other epidermoid cysts of the jaws.