Histoenzymological features of epithelial cells in epidermoid carcinomas of oral mucosa and in ameloblastomas of jaws.

An histoenzymological study comprising oxidative enzymes, diaphorases, acid and alkaline phosphatases, naphtolesterases, referred to 60 biopsy and operation specimens. It showed interesting arguments for diagnosis and understanding of precancerous and cancerous lesions of the oral mucosa and also of ameloblastomas of jaws. The enzymatic activities of precancerous and cancerous oral lesions were compared with those of normal buccal mucosa and epidermis, benign hyperkeratosis (activities similar to those of the epidermis) and lichen planus. In severe dysplasia and epidermoid carcinoma, numerous variations of oxidative, esterase and acid phosphatase activities were seen from one cell to another. But this pattern was non conclusive for the diagnosis, a similar one being found in inflammatory lesions and especially in the lichen planus. In lobules of invasive carcinoma, the strong enzymological activities (particularly acid phosphatases, naphtolesterases) were correlated with a high degree of differentiation of the tumor and these enzymatic methods offered an interesting contribution for the fine evaluation of histoprognosis in malignant epithelial tumors. Among the lesions of jaws, radicular and dentigerous cysts had low enzymatic activities similar to those of normal buccal epithelium. The epidermoid cysts (keratocysts), because of their highly differentiated keratinization, like benign hyperkeratosis, had the same enzymatic activities as epidermis. Peculiar were the enzymatic activities of common ameloblastoma; they differed from those of other lesions of squamous tissues (low oxidative activities without decreasing gradient). Besides, round epithelial clumps, the stroma showed a high and widespread alkaline phosphatase activity. Thus, this peculiar stromal activity may be useful to differentiate ameloblastoma from the other epidermoid cysts of the jaws. In the other hand, such a constatation suggests a low degree of odontogenic induction.