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BENIGN TUMORS OF THE EPITHELIAL TISSUE ORIGIN II
INDIAN DENTAL ACADEMYLeader in continuing Dental Education
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OBJECTIVES
At the end of the lecture student should be able to
• Describe classification, incidence, etiology, clinical features histopathological features of nevus.
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PIGMENTED CELLULAR NEVUS(pigmented mole, benign melanotic nevus)
DEFINITION• defined as a congenital, developmental tumor- like
malformation of the skin or the mucous membrane
CLASSIFICATION• Intradermal nevus (common mole)• Junctional nevus • Compound nevus • Spindle cell &/ or epitheloid cell nevus • Blue nevus
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Clinical features • Congenital nevus- small or garment nevi• Small- 3-5 cms • Large- 10 cms• Congenital seen in 1-2.5% in neonates
-Intraoral occurrence rare
• Acquired nevus- common• 8th mnth of life increases with age• Increases in no. with age• Peak in late third decade of life
• Intra dermal nevus-several/ dozens scattered over the body-smooth flat lesion or may be elevated -may/may not exhibit brown pigmentation-strands of hair growing from the surface
Melanocytes
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• Junctional nevus -similar to intradermal nevus-distinctly diff histologically
• Compound nevus-composed of intradermal nevus & overlying junctional nevus Pigmented nevus cells
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Spindle cell/ epitheloid cell nevus
-in children
-similar to malignant melanoma
-clinically benign but histologically malignant
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Blue nevus
-true mesodermal composed of dermal melanocytes-rarely malignant change-occurs on buttocks, dorsum of feet & hands-present at birth & persists-smooth & hair grows from its surface -brown – blue / bluish- black
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• Oral manifestations-hard palate, buccal mucosa, lip & gingiva-raised pigmented areas
• Histological features-large discrete cells, ovoid vesicular nucleus & pale cytoplasm -sheets or cords may contain granules of melanin in their cytoplasm-arrangement of cells in theques
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• Intradermal nevus -nevus in the CT is seperated from the epith by definite band of connective tissue -nevus cells not in contact with epithelium
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zone of demarcation absent -nevus cells blend with the epithelium
-overlying epithelium- thin & irregular & crosses the junction giving a dropping or abtropfung effect
-Tendency to undergo transformation into malignant melanoma.
Junctional nevus
Compound nevus
• -Shows features of both junctional and intradermal nevus. -nests of nevus cells & dropping off from the epidermis-large nest present in the dermis
• Blue nevus
-common/cellular blue nevus
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-common- large melanocytes with large dendritic processes parallel to epidermis-no junctional activity
-cellular – large round or spindle cell with pale vacuolated cytoplasm-cells arranged in an alveolar pattern
TreatmentSurgical excision
Melanin pigment
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Summary • Classification• Incidence• etiology• Clinical features• Histological features of nevus.
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THANK YOU !
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