1. Dermatopathology Kimiko Suzue, MD PhD October 25 and 27, 2011

3. Dermis
Papillary dermis - the thin upper layer - of the dermis - lies directly below and interdigitates with the epidermal rete ridges.  The papillary dermis is composed of loosely interwoven collagen (Collagen III)
Thicker reticular dermis with its coarser and horizontally running bundles of collagen
(Collagen I)  

4. Verruca vulgaris Verrucous/papillomatous epidermal hyperplasia
Hyperkeratosis
Prominent keratohyaline granules
Koilocytes

5. Verruca vulgaris

6. Verruca plantaris (plantar wart)
Point out black dots in these warts, ie thrombosed capillaries

7. Verruca vulgaris (common warts)

8. Seborrheic Keratosis Small keratin-filled cysts (horn cysts)
Down-growth of keratin into main tumor mass (pseudo-horn cysts)
Benign proliferation of basaloid keratinocytes

9. Actinic Keratosis Solar elastosis Parakeratosis (arrow) Atypia
(dermis looks purplish/sun damgae)
Parakeratosis (arrow)
Atypia
(nuclei in bottom portion of epidermis are hyperchromatic/enlarged)
Inflammation
Not full-thickness atypia

10. Actinic Keratosis

11. SCC in situ - Histopathology
Highly atypical cells at all levels of the epidermis
Abundant mitoses, crowding of nuclei, pleomorphism, ± necrosis
Cells keratinize and stain for keratin
Bowen disease

12. Invasive SCC
Endophytic growth of atypical epithelium with patchy lymphocytic infiltrate
Cells have broken through basement membrane
Haphazardly oriented lobules of varying shapes & sizes within the dermis
Squamous pearls: whorled aggregates of parakeratotic horn
Mild to severe cytologic atypia

13. Basal Cell Carcinoma - Histopathology
Nodular masses or cords of darkly staining cells with high nucleus to cytoplasm ratio
In 90% of cases, a connection to the epidermis can be seen

14. Basal Cell Carcinoma

15. Malignant Melanoma CLINICAL FEATURES: A B C D E Asymmetry
Border irregularity
Color variegation
Diameter > 0.6 cm
Evolution

16. Superficial spreading melanoma

17. Superficial spreading melanoma

19. Acral Lentiginous Melanoma

20. Malignant Melanoma HISTOPATHOLOGY: Asymmetry Architectural disorder
Single-cell proliferation, not just nests
Pagetoid spread: melanocytes above basal layer
Cytologic atypia, usually severe

21. Malignant melanoma

22. Tumor Thickness as Sole Predictor of Outcome 10 years after Definitive Therapy of Primary Melanoma
Breslow Thickness (mm) Survival (%)
≤ –88
1.01– –79
2.01– –64
> –54

23. Psoriasis

24. Psoriasis-Morphology
Acanthosis- marked epidermal thickening
Overlying parakeratotic scale
Auspitz sign-Vessels in dermal papillae bleed eaily when scale is removed
Munro microabscess-neutrophil microabscess in parakeratotic stratum corneum

25. Psoriasis

26. Psoriasis