1. Intradermal Nevous

2. ACQUIRED MELANOCYTIC NEVUS (MOLE)
a benign, localized proliferation of nevus cells (originated from the neural crest)………..their ability to produce melanin
These melanocytic cells migrate to the epidermis during development lesions may first appear shortly after birth.
the most common of all human "tumors
Intraoral lesions occur but are not common

3. several clinical stages
which tend to correlate with specific histopathologic features.
The earliest presentation
microscopically as a junctional nevus
A sharply demarcated, brown or black macule
<6 mm in diameter
this lesional appearance may persist into adulthood

4. compound nevus
more often the nevus cells proliferate over a period of years to produce a slightly elevated, soft papule with a relatively smooth surface
The degree of pigmentation becomes less
most lesions appear brown or tan

5. intradermal nevus the nevus usually remains less than 6 mm in diameter
As time passes…….. ……….loss of pigmentation
the surface may become somewhat papillomatous
hairs may be seen growing from the center
the nevus usually remains less than 6 mm in diameter

6. Origin of nevus cells…….
histopathologic Features
a benign, unencapsulated proliferation of small, ovoid cells
( nevus cells)…….
tend to be organized into small, round aggregates (theques).
Origin of nevus cells…….
from cells that migrate from the neural crest to the epi. and submucosa
or from altered resident melanocytes

7. The lesional cells have small, uniform nuclei and a moderate amount of eosinophilic cytoplasm, with indistinct cell boundaries
lack the dendritic processes
A characteristic microscopic feature:
that the superficial nevus cells tend to be organized
into small, round aggregates (theques).

8. classified histopathologically according to their stage of development

12. Zones of differentiation often are seen throughout the lesion.
type A: The superficial cells ………larger and epithelioid, with abundant cytoplasm, frequent intracellular melanin, and a tendency to cluster into theques

13. type B: Nevus cells of the middle portion of the lesion……
type B: Nevus cells of the middle portion of the lesion…….. less cytoplasm, are seldom pigmented, and appear much like lymphocytes

14. type C: Deeper nevus cells appear elongated and spindle shaped, much like Schwann cells or fibroblasts

15. 1
1-Theque
2-Hair Follicle 2

17. 1-Theque 1

18. The end