Oral Submucous Fibrosis: Definition, Etiopathogenesis, and Histopathology

Oral Submucous Fibrosis: Definition, Etiopathogenesis, and Histopathology

Question. Define oral submucous fibrosis. Describe in detail the etiopathogenesis and histopathology of the same.

Answer.

Submucous Fibrosis

OSMF is defined as “An insidious chronic disease affecting any part of the oral cavity and sometimes the pharynx.

Although occasionally preceded by and/or associated with vesicle formation, it is always associated with juxta­epithelial inflammatory reaction followed by fibroelastic changes in lamina propria, with epithelial atrophy leading to stiffness of oral mucosa and causing trismus and inability to eat.” — Pindborg (1966)

“Understanding oral submucous fibrosis through FAQs: Q&A explained”

Oral Submucous Firosis Etiopathogenesis

OSMF

• Betel nut: Tannic acid and arecoline present in betel nut affect the vascular supply of oral mucosa leading to a neurotropic disorder. Nitrosation of arecoline causes the formation of nitrosoguvacine and nitrosoguvacoline as well as 3-methyl-nitrosamino propionitrile which leads to alkylation of DNA. Metabolism of nitrosoguvacine and nitrosoguvacoline as well as 3 methyl nitrosamino propionitrile, causesthe formation of cyanoethyl. Cyanoethyl interacts with O’ methyl guanine in DNA. Constant ir­
  ritation by this leads to OSMF and exposure for long time leads to malignant transformation.
  Recent concept: Arecoline in betel nut stimulates fibroblasts. Fibroblasts proliferates and produce collagen. Flavonoids, i.e. catechin and tannin in betel nut stabilizes collagen fiers which make them resistant to degradation by collagenase enzyme. Trismus is caused due to juxta­epithelial hyalinization as well as involvement of the secondary muscles. Increased muscle activity leads to glycogen depletion and reduced blood supply due to connective tissue changes leads to degeneration of muscle and also cause firosis.

“Importance of studying oral submucous fibrosis for better diagnostic outcomes: Questions explained”

• Tobacco and lime: Tobacco act as a local irritant which leads to OSMF. Lime causes local irritation as well as vesicle and ulcer formation in the oral mucosa.
• Chilies: Capsaicin is an active ingredient present in red chillies. It is the irritant in chillies which leads to oral submucous firosis.
• Hereditary: Presence of genetic susceptibility is present.
  Familial occurrence of OSMF is seen.
• Immunological Studies: It was found that human leukocyte antigen (HLA) A10, B7 and DR3 occur signifiantly more frequently in oral submucous firosis.