Oral Submucous Fibrosis — ORE Part 1 MCQ
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Correct answer: D — Betel (areca) nut chewing
Explanation lettering: E = shown as A · D = shown as B · A = shown as D · B = shown as E
The answer is A: Betel (areca) nut chewing. Oral submucous fibrosis (OSF) is a chronic, progressive, potentially malignant condition characterised by submucosal fibrosis and progressive trismus (restricted mouth opening). The International Agency for Research on Cancer recognises areca nut chewing—specifically its active alkaloid arecoline and copper content—as the primary aetiological agent. Arecoline induces fibroblast dysfunction, excessive collagen deposition, myofibroblast activation, and reactive oxygen species generation, leading to the hallmark fibrotic bands and loss of oral elasticity. While scleroderma (B) and radiotherapy (C) can cause oral fibrosis and trismus, neither produces the specific pattern of OSF; scleroderma is a systemic autoimmune condition affecting multiple organs, and radiotherapy causes localised scarring rather than the characteristic submucosal fibrosis of OSF. Myasthenia gravis (D) and tetanus (E) are neuromuscular disorders causing muscle weakness or rigidity, not fibrotic tissue changes. OSF occurs predominantly in populations with betel nut chewing habits (South Asia, Southeast Asia, Pacific) and is now a recognised potentially malignant oral disorder.
Reference: Oral submucous fibrosis: pathogenesis and therapeutic approaches. NCBI PMC, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11785813/ (2025); Oral submucosal fibrosis: a comprehensive review on pathogenesis, diagnosis, therapeutics and computational advances. NCBI PMC, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12872905/ (2025).