Table 2. Histopathological features of OSMF and SSc.

OSMF: oral submucous fibrosis; SSc: scleroderma

	OSMF	SSc: associated oral manifestation features
Characteristic Findings	1. Sub-epithelial inflammatory reaction	1. Perivascular inflammatory infiltrate
	2. Juxta-epithelial hyalinization degenerative and atrophic changes in muscular layer fibrosis	2. Increased extracellular matrix, thickened blood vessels, loss of dermal papillary structures, fibrosis
Histological Stages	Stages - inflammation, hyalinization, fibrosis, malignant transformation	Stages - inflammation, vasculopathy, fibrosis/sclerosis
Epithelium	Atrophic epithelium showing dysplastic changes at the later stages with loss of rete ridges	Normal or atrophic/flattened superficial layer with loss of rete ridges. Nodular collection of lymphocytes at the dermal-subcutaneous junction
Connective tissue stroma	1. Granulation, degenerative, and atrophic changes in the muscular layer. 2. Fibrosis - complete collagen hyalinization, obliterated blood vessels, lymphocytes, and plasma cells, dense band of collagen bundles. 3. Malignant transformation - dysplasia, erythroplakia, and changes into squamous cell carcinoma	1. Vasculopathy - edematous endothelial cells Submucosal hyalinization with thickening of blood vessels. Later stages show the disappearance of subcutaneous fat and severe sclerosis at the walls (intima) of the blood vessels. 2. Fibrosis/Sclerosis-thickening& hyalinization of the collagen fibers in the skin. 3. Deposition of collagen fibers (sclerosis) at the reticular layer. 4. Atrophy, degeneration, and drop out of adnexal structures “entrapped” by excessive collagen deposition