Oro-facial Precancerous States - 1

By Dr. Vishaal Bhat on Wednesday, 7 November, 2007 with 0 comments

The term precancer was used for the first time by dermatologist Dubreuilh in 1896. He derived the term from a clinical experience on some skin lesions that regularly transform into malignant forms. The term precancers designates states and lesions that may transform into a carcinoma. There are also pre-sarcomatoses giving a rise to sarcomas and pre-melanomatoses from which a malignant melanoma originates. All these conditions are generally named as pre-blastomas or pre-neoplasias. At the general medical knowledge, the term precancer is used (not entirely accurately) to describe all pathological lesions that can be a basis for malignant tumorous growth.

Due to the fact that tumors of the oro-facial and stomatological areas are carcinomas in 90% of all cases, it would not be such a mistake to use the common term precancer for pre-neoplastic conditions and lesions at the above described anatomical area. It would be apt to remind here that the term precancer is not definite but relative one, since not all precancers get malignant and not all malignant tumors are derived from precancers. Such relativity by no means decreases the significance of precancerous conditions for etiology and pathogenesis of malignant neoplasias and the oncological prevention (the secondary prevention). For these reasons, clinical oncologists, in concordance with onco-pathologists, recommend to divide the precancerous conditions into those of the narrowest and widest sense of the term.

Precancers in the wide sense are termed as precancerous conditions or facultative precancers. Basically, they are initial affections of the skin of the face and the oral cavity mucosa that are predetermined with a statistically high probability for transformation into a precancer (in the narrowest sense) itself. The list of facultative precancers includes chronic contact dermatoses and mucosidoses (e.g. tar or nicotine induced), electrochemical mucosidoses and glossitises, chronic radiodermatosis, inflammatory and atrophic damages by irradiation with light rays (cheilitis of sailors and agricultural workers) and initial forms of xeroderma pigmentosum. Some forms of simple leukoplakias (transitory, exogenously induced) can be mentioned at this group, as well as the Sjรถgren’s syndrome which can give rise to a lymphoma with malignant properties, upon chronic non-bacterial sialadenitis (sialosis). We should not overlook odontogenous cysts whose epithelium is also prone to malignant changes and last, benign tumors of the skin and skin adnexa (especially pigmented ones) of the face and the oral mucosa(papillomas).

The above mentioned conditions manifest themselves as clinical units and their facultative transformation into an obvious precancer can be proven upon histo-pathological examination only. It is a matter of experience and predictability, if and when these altered tissues should be verified bioptically. Less experienced physician should consult such cases with a specialist.

Precancers in the narrow sense are termed as precancerous lesions or obligatory precancers. They are often (but not always) derived from corresponding initial forms of facultative precancers. In order to diagnose obligatory precancers, it is necessary to perform cytological and histological verification of markers, characteristic for precancers. Skin and mucous precancers originate on the etiological basis of both endogenous and external factors. Endogenous (disposition) factors are genetic, race- and constitution-related, and immunological. Exogenous (exposition) factors are both physical effects (mainly radiation) and chemical (carcinogenic compounds). An individually specific constellation of both disposition and exposition factors may result in formation of favorable conditions for initialization of precancerous states (in the widest sense).

Category: Stomatology Notes



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