All about of Oral Submucous Fibrosis

On the Indian subcontinent, the use of smokeless tobacco in various forms is very popular. This habit, which usually involves the chewing of a betel quid (combined areca nut, betel leaf, tobacco and slack lime), has led to the development, in a large proportion of users, of a unique generalized fibrosis of the oral soft tissues, called oral submucous fibrosis.  While not producing soft tissue masses in the usual sense, the fibrosis may be confused with generalized fibromatosis, hence, is included in this section of the present chapter.
The condition is found in 4/1,000 adults in rural India, and is caused by the areca nut in the quid. Additionally, it is estimated that as many as 5 million young Indians are suffering from this precancerous condition as a result of the increased popularity of the habit of chewing pan masala. It results in a marked rigidity with progressive inability to open the mouth.  There is a fibroelastic transformation of the juxta-epithelial connective tissues and an increased risk of oral carcinoma from the tobacco of the quid.

Clinical Features

Submucous fibrosis typically affects the buccal mucosa, lips, retromolar areas and the soft palate. Occasional involvement of the pharynx and esophagus is seen. Early lesions present as a blanching of the mucosa, imparting a mottled, marble-like appearance. Later lesions demonstrate palpable fibrous bands running vertically in the buccal mucosa and in a circular fashion around the mouth opening or lips.  As the disease progresses the mucosa becomes stiff, causing difficulty in eating and considerably restricting the patient's ability to open the mouth (trismus). If the tongue is involved, it becomes stiff and has a diminished size.
Mucosal petechiae are seen in more than 10% of cases and most patients complain of a burning sensation, often aggravated by spicy foods.  Salivary flow is diminished and blotchy melanotic mucosal pigmentation is often seen. More than a fourth of affected persons develop precancerous leukoplakia of one or more oral surfaces. Once present, oral submucous fibrosis does not regress, either spontaneously or with cessation of betel quid chewing.

Pathology and Differential Diagnosis

The early cases of oral submucous fibrosis present as chronic inflammatory cell infiltration of subepithelial connective tissues. This otherwise nonspecific infiltrate usually contains a number of eosinophils, cells seldom found in oral inflammation. Older lesions demonstrate a reduced vascularity, reduced numbers of inflammatory cells, and dense bundles and sheets of collagen immediately beneath the epithelium. The eventual thick band of hyalinized subepithelial collagen shows varying extension into submucosal tissues, typically replacing the fatty or fibrovascular tissues normal to the site.
Minor salivary glands in the area of habitual quid placement often demonstrate a chronic inflammatory infiltrate and replacement of acinar structures by the hyalinized fibrosis. The hyalinized stroma can be distinguished from the amyloid infiltration of amyloidosis through the use of Congo red staining and thioflavin-T staining under polarized and immunofluorescent light.
The epithelium is atrophic, with or without excess surface keratin, and demonstrates intercellular edema. A fourth of the biopsied cases will demonstrate epithelial dysplasia at the time of biopsy. When squamous cell carcinoma is seen, it has the same features of carcinoma as those seen in persons without the betel quid chewing habit.

Treatment and Prognosis

There is no effective treatment for oral submucous fibrosis and the condition is irreversible once formed.  Plastic surgery may be required to allow for improved opening of the mouth. Surface leukoplakias are handled by close follow-up and repeated biopsies of areas of severe involvement. All dysplasias and carcinomas are treated in the routine manner for those entities. Epidemiological studies have shown that as many as 10% of oral submucous fibrosis patients develop an oral carcinoma. Since the tobacco is the component of the quid most associated with cancer development, cessation of the quid chewing habit or eliminating the tobacco from the quid will reduce the risk of oral cancer. Likewise, a certain proportion of precancerous keratoses will diminish or disappear with habit cessation.


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