1. Oral Cavity Pathology Last Updated: Oct. 3, 2006

2. Lichen Planus variable and present as white striations (Wickham striae), white papules, white plaques, erythema (mucosal atrophy), erosions (shallow ulcers), or blisters. The lesions predominantly affect the buccal mucosa, tongue, and gingivae, although other oral sites are occasionally involved. a T-cell–mediated autoimmune disease in which autocytotoxic CD8 + T cells trigger the apoptosis of oral epithelial cells Slightly increased risk of oral SCCa

3. Lichen Planus Spider web. The buccal mucosa involved most often reticular form most common

5. Reticular Oral Lichen Planus

7. Lichen Planus A very high power view of the dermoepidermal junction Civatte bodies (arrows), keratinocyte enlargement, and coarse collagen bundles are illustrated.

8. Reference E-Medicine Article: –http://www.emedicine.com/derm/topic663.h tm

9. Leukoplakia Definition: a whitish patch or plaque that cannot be characterized clinically or pathologically as any other disease, and is not associated with any physical or chemical causative agent, except the use of tobacco. between 5% and 25% of these lesions are premalignant

10. Leukoplakia: Etiology No etiologic factor can be identified for most persistent oral leukoplakias (idiopathic leukoplakia). Known causes of leukoplakia include the following: –Trauma (eg, chronic trauma from a sharp or broken tooth or from mastication may cause keratosis) –Tobacco use: Chewing tobacco is probably worse than smoking. –Alcohol –Infections (eg, candidosis, syphilis, Epstein-Barr virus infection): Epstein-Barr virus infection causes a separate and distinct non– premalignant lesion termed hairy leukoplakia. –Chemicals (eg, sanguinaria) –Immune defects: Leukoplakias appear to be more common in transplant patients.

11. Homogeneous Leukoplakia

12. Erythroleukoplakia

13. Verrucous or Nodular Leukoplakia

14. Carcinoma(leukoplakia appearing)

15. Leukoplakia- Histopathology Features highly variable –Ranging from hyperkaratosis and hyperplasia to atrophy and severe dysplasia –Significant intrapathologist and interpathologist variation in diagnosing dysplasia –Molecular studies indicated

16. Erythroplakia (Erythroplasia) A CLINICAL entity that carries no pathological connotation a red and often velvety lesion, which, unlike leukoplakias, does not form a plaque but is level with or depressed below the surrounding mucosa. Red oral lesions usually are more dangerous than white oral lesions. Carcinomas are seen 17 times more frequently in erythroplakias than in leukoplakias, but leukoplakias are far more common

17. Erythroplakia 75-90% carcinoma or carcinoma in situ or show severe dysplasia. Erythroplasia affects patients of either sex in their sixth and seventh decades and typically involves the floor of the mouth, the ventrum of the tongue, or the soft palate.

18. Erythroplakia

19. Reference: Kumar: Robbins and Cotran: Pathologic Basis of Disease, 7th ed., Copyright © 2005 Saunders

20. Oral Hairy Leukoplakia Whittish corrugated thickening of mucosa on lateral tongue border Occurs almost exclusively in HIV- infected patients –Probability of developing AIDS is 50% at 16 months and 80% at 30 months in patients with hairy leukoplakia EBV present in tissue

21. Oral Hairy Leukoplakia

22. References E-Medicine Article: Leukoplakia –http://www.emedicine.com/derm/topic227.h tmhttp://www.emedicine.com/derm/topic227.h tm E-Medicine Article: Oral Mucosa Cancers –http://www.emedicine.com/derm/topic227.h tmhttp://www.emedicine.com/derm/topic227.h tm

23. Oral Cancer-Progression Reference: Kumar: Robbins and Cotran: Pathologic Basis of Disease, 7th ed., Copyright © 2005 Saunders, An Imprint of Elsevier

24. Oral Squamous Cell Carcinoma Carcinoma in situ.

25. Oral Squamous Cell Carcinoma Invasive

26. Oral Squamous Cell Carcinoma ominous characteristic of squamous carcinoma is its ability to surround nerves and to infiltrate for long distances in a perineural fashion

27. Oral Squamous Cell Carcinoma marked hyperchromatism and extremely atypical mitoses

28. Oral Squamous Cell Carcinoma Many nuclei show clumping of chromatin. There is an abnormal mitotic figure in the center of the photomicrograph.

29. Oral Squamous Cell Carcinoma Most cells are easily identifiable as squamous cells. At one end there is a mass of parakeratin ("keratin pearl").

30. Squamous Cell Carcinoma

31. Desmosomal bridges between cells. Abundant organophilic (keratinized) cytoplasm, Extracellular squamous pearls, ("keratin pearl"). Nuclear anaplasia., hyperchromatism. Frequent abnormal mitosis.