Clinical and histological indicators for malignant transformation of oral submucous fibrosis: an analysis of cases from a tertiary care center

Abstract

Background: Oral submucous fibrosis (OSMF), a potentially malignant disorder predominantly affecting South Asian populations, is characterized by irreversible progression and significant malignant transformation potential. Early identification of risk indicators is crucial for implementing preventive measures and appropriate interventions to curb disease progression. While clinical parameters and histological features have been studied independently, comprehensive analyses evaluating multiple clinical manifestations, histopathological characteristics, and their correlations remain limited, particularly in long-term studies. This study aimed to assess individual clinical and histological parameters, and evaluate their relationships to identify early indicators of malignant transformation, thereby enabling more effective early intervention strategies.

Methods: A retrospective analysis of electronic records from January 2012 to July 2024 was conducted on 118 OSMF patients aged 20-70 years, excluding those with concurrent mucosal lesions or incomplete records. Clinical parameters, including fibrous bands, burning sensation, mouth opening (measured by Vernier caliper), ulceration, and mucosal blanching, were graded based on Haider's classification, while histopathological features such as epithelial thickness, keratinization, blood vessel characteristics, signet ring cells, inflammatory infiltration, and hyalinization were graded according to Pindborg and Sirsat's classification. Data analysis was performed using Jamovi Software, employing descriptive statistics and chi-square tests to assess categorical data, with statistical significance set at p < 0.05.

Results: Among 118 OSMF patients (89.8% males, mean age 41 years), buccal mucosa was predominantly affected (93%). Major clinical features included burning sensation (87.3%), blanching (95.8%), and fibrous bands (96.6%). Of 106 patients, 41.5% showed Stage 1 mouth opening (> 20 mm), with 60% of malignant transformations occurring in this group. Histopathologically, 49.2% cases were moderately advanced, showing atrophic epithelium (56%), keratinization (85.6%), and juxta-epithelial hyalinization (92.4%). The study revealed a 4.2% malignant transformation rate, with epithelial dysplasia observed in 27% cases.

Conclusions: The study highlights the significance of early diagnosis, as even in the initial stages of OSMF (mouth opening < 20 mm, grade 1), there were advanced histological changes that were observed along with a risk of malignant transformation. The observed rate of malignant transformation was 4.2% and hence prompt identification of the clinical and histological indicators for malignant transformation can help in improving patient outcomes.

Keywords: Histopathology; Malignant transformation; Oral submucous fibrosis; Potentially malignant oral disorders.

Fig. 1

(a) Photomicrograph showing an atrophic epithelium with loss of rete ridges (red arrows) with juxta epithelial hyalinization (black arrow) (H&E 10X). (b) Photomicrograph showing a juxta epithelial hyalinization (red arrow) and degeneration of muscle tissue (black arrows) (H&E 10X). (c) Photomicrograph showing dense inflammatory infiltrate of lymphocytes (red arrows) (H&E 10X). (d) Photomicrograph showing signet cells in the epithelium (red arrows) (H&E 20X) in oral submucous fibrosis

Fig. 2

Photomicrograph showing variations in the diameters of the vascular channels in the study subjects with oral submucous fibrosis (H&E 100 μm: 10X, 20 μm: 40X)