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The oral mucous membrane reacts to various forms of injurious stimuli and develops lesions if the stimuli or noxious influences are sufficient to produce disease. Lesions occurring on the oral mucosa may be of several distinct clinical forms, and a similar type of gross lesion may be produced by a large variety of entirely different agents. The appearance of the gross lesion is usually insufficient for adequate diagnosis. Distribution of the lesions, clinical history, and past history may have some diagnostic value, but microscopic examination is often necessary for exact diagnosis. The microscopic features of a lesion may be nonspecific, and diagnosis can be made only by painstaking correlation of gross appearance, clinical history, and microscopic findings. In general, the diagnosis of oral lesions depends upon an evaluation of both clinical and microscopic features.
GROSS OR CLINICAL LESIONS
     Essentially, all diseases of the oral mucosa are manifested clinically by the appearance of grossly visible or macroscopic lesions. These lesions comprise a surprisingly small number of basic types or forms: macule, papule, plaque, vesicle, bulla, pustule, ulcer, erosion, nodule, tumor, atrophic area.
     Macule. A macule is a circumscribed, non - raised area of altered coloration varying in size from a pinhead to several centimeters in diameter. Macules are usually deeper in color than the surrounding normal mucosa and may be red, red-brown, or brown-black. A macular eruption or rash may represent punctate hemorrhages or petechiae as seen in scurvy or thrombocytopenic purpura, melanin deposition as in Addison' s disease, or small vascular malformations as in hereditary telangiectasia. Macules may vary in shape from circular to ovoid to somewhat linear.
     Papule. A papule is a small, circumscribed, solid, elevated area varying in size from a pinhead to 5 mm. The base is round or ovoid, and the surface configuration may be pointed, rounded, or flattened. A papular eruption on the oral mucosa usually consists of large numbers of individual pinbead lesions arranged in varying patterns. The color of papules on oral mucous membrane is usually gray-white, and the gross lesion composed of numbers of papules may be white. Lichen planus, an inflammatory dermatosis, appears as a typical papular eruption of the oral mucosa, with papules arranged in lacelike, plaquelike, or even annular patterns.
     Plaque. A plaque is a small or large, raised, firm: clearly demarcated area of gray or white coloration. The surface texture may be relatively smooth or rough and pebbled. Cracks or fissures may divide the lesion. Leukoplakia, carcinoma, and discoid lupus erythematosus may appear as plaques. Multiple, closely placed papules may resemble a plaque superficially, but careful examination with a magnifying glass will reveal the punctate lesions, such as lichen planus, rather than the continuous plaque lesion .
      Vesicle. A vesicle is a small (2 to 5 mm), circumscribed, elevated lesion composed of a thin surface covering overlying and containing an accumulation of fluid. A vesicular eruption may consist of a single lesion or multiple lesions in different stages of formation and healing.      The covering or vesicular membrane may be thin and delicate or thick, depending upon whether the vesicle is subepithe本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。