No abstract

Oral submucous fibrosis (OSF) is a chronic disease of the oral cavity characterized by an inflammatory reaction followed by severe fibro-elastic changes. The aim of the present study was to investigate the three-dimensional morphological changes in the connective tissue cores (CTCs) of the oral mucosa in OSF. The sample consisted of buccal mucosal biopsies from ten human subjects ranging in age from 40-45 years; five of them were clinically diagnosed as having moderate to severe OSF, and the remaining five served as unaffected controls. Half of each biopsy was formalin-fixed and paraffin-embedded for light microscopy, while the other half was fixed in a Karnovsky's solution, treated with HCl to exfoliate the epithelium, and processed for examination under a scanning electron microscope (SEM). Oral submucous fibrosis biopsies exhibited heavily packed aldehyde fuchsin-positive fibers (i.e. elastic fibers) in the submucosa under the light microscope. Broad bundles of collagen fibers were seen in a concentrated manner in the deeper layers. Scanning electron microscopy of the buccal mucosa in OSF showed the finger-shaped CTCs to be attenuated beneath the epithelium at the initial stages of the disease. Patchy degenerative areas lacking the CTCs were observed in advanced cases. These degenerative areas increased gradually with the progression of the disease. Highly fibrosed cases showed severe degeneration of the CTCs, resulting in a smoothening of the connective tissue surface in the buccal mucosa.

The cell proliferation status of 60 oral squamous cell carcinomas from Sri Lankan subjects was examined by immunohistochemistry using the Ki-67 index. A comparison was made between the indices derived from the centre of the tumours and those derived from the invasive fronts of the same tumours. There was a positive correlation between the two indices suggesting a clonal expansion of malignant cells, but the mean index derived for the invasive fronts (29.75 11.64) was significantly higher than the mean index for the body of these tumours (25.65 11.64). Thus, at a given time, more peripheral cells at the invasive front are proliferating and this compartment is likely to be more informative in prognostic and other behavioural studies involving the cell cycle. In squamous carcinomas, increased and uncontrolled cell proliferation at the invasive front may be one feature contributory to the invasion.

Background: Clinical stage and pathology grading have consistently failed to predict survival in patients diagnosed with oral squamous cell carcinoma (OSCC). There is a need to develop a grading system that could have a predictive value in assessing the prognosis of patients with OSCC. The aim was to evaluate the prognostic significance of several parameters of the modified Bryne's malignancy grading system. Methods: Malignancy grading of invasive fronts of 60 OSCCs from Sri Lankan subjects was undertaken using Bryne's criteria. Results: Of the five morphological features assessed at the invasive fronts of the tumours, the range of scores derived for keratinization was low, and the host response in the stromal tissue was marked compared with reported series from European countries. There were no tumours scoring a malignancy grading under 9, regarded as tumours with a 'good prognosis'. In logistic regression analysis among patient factors, age had a positive association on survival, and among tumour factors, the malignancy grading was significantly predictive of overall survival. Conclusions: Bryne's malignancy grading is predictive of overall survival in patients with OSCCs.