6-Skin tumors(benign and Malignant).pptx

Skin tumors

1. SKIN TUMORS

2. Identify different types of benign and malignant skin tumors. List Epidermal benign and malignant tumors. Discuss Melanocytic tumors of the skin. Explain the main signs of Malignant Melanoma. Learning Objectives

3. Tumors of skin Epidermis Dermis Skin appendages Melanocytic tumors Vascular tumors

4. Epidermal tumors / Benign : 1. Seborrheic keratosis : Common in middle age or older individual. Rarely ( if multiple )  represent para- neoplastic syndrome (GIT ). Round, coin-like brown plaques Located mostly on the trunk , limbs & head.

5. Proliferation of uniform, basaloid (small) keratinocytes with hyperkeratosis. Keratin filled cysts (horn cysts) and pseudo-horn cysts. Histology

6. 2. Actinic Keratosis : Due to excessive , chronic exposure to sunlight → Fair skined middle-aged & elderly pts  Face & hands … Considered as “ premalignant ” with p53 mutation , rate of progression 0.1%-2.6% per year Red & scaly lesions  sandpaper-like . Epidermal tumors / Benign :

7. Atypical keratinocytes at basal layer . Hyperkeratosis with parakeratosis . Uncommonly , Full thickness dysplasia  SCC i n situ  may progress to invasive Squamous Cell CA Morphology & Histology

8. Hyperkeratosis Parakeratosis Dysplasia  CA in Situ

9. Epidermal tumors / Malignant : Basal Cell Carcinoma Squamous Cell Carcinoma The commonest types & majority present on sun exposed skin

10. 1. Basal cell carcinoma : Most common malignant tumor in patients over 40´s with fair skin . Due to sun exposure  F ace ( never mucosal ). Sporadic or familial ( GORLIN’S Syndrome ). Infiltrative , slowly growth with RARE METASTASES. Pathogenesis : PTCH gene mutation involved in Hedgehog pathway P53 mutation ( poor Px ). Epidermal tumors / Malignant :

11. Morphology & Histology Gross : Papule with telangiectasia (could be pigmented). RODENT ULCER . Histology: : Nests of epithelial cells that resemble basal cells with peripheral PALISADING and separated from surrounding tissue by a CLEFT-LIKE space.

12. Cleft

13. 2. Squamous Cell Carcinoma Develops in sun-exposed skin of fair patients . Mucosa may be affected (oral) Etiology : Exposure to UVB light  DNA damage (p53 ) Actinic keratosis & in situ CA. Arsenicals & industrial carcinogens . Ionizing radiation . Chronic scarring ulcers , burns , fistula… etc Immunosuppression (HPV 16 & 18). Xeroderma pigmentosum . Epidermal tumors / Malignant :

14. Gross : From smal scaly lesion to large nodule or ulcer ( later ). Microscopic : Invasive squamous cell carcinoma with variable degrees of keratinization . It has an increased tendency to infiltrate and metastasize locally to regional lymph node Morphology & Histology

15. Melanocytic Tumors of the Skin

16. Commonest benign tumor in the body . Derived from dendritic melanocytes present in basal layer of the epidermis. Somatic gain of function mutation in BRAF or RAS. There are several forms : Junctional , compound & intradermal . 1. Melanocytic Nevus (Mole/ Melanocytic nevus ).

17. Morphology & Histology Gross : Uniform macule, papule or nodule , tan/ brown color with sharp margin & tendency to be stable in size & shape . Histology : Nests or cords of uniform nevus cells + melanin pigment Malignant transformation is uncommon .

18. 2. Dysplastic Nevus Considered as a marker for future melanoma Sporadic  L ow risk of transformation. Familial (AD)  M elanoma risk up to 100 %. Usually larger (>5mm), multiple  O n sun exposed & non-exposed skin. Activating BRAF or RAS mutations Histology: Compound nevus with increased cellularity , cytological atypia , dermal fibrosis around proliferating cells

19. Less common than BCC & SCC but much more deadly. Its incidence has increased. More in New Zealand & Australia. Sporadic (e.g UV) OR Familial ( >5%-10%) Sites : Skin, mucosa, eye, esophagus, meninges …etc 3. Malignant melanoma

20. Predisposing factors Sunlight UV exposure on exposed white skin Familial dysplastic nevus syndrome Many gene mutations ( inactivation  CDKN2A , & activation  BRAF,RAS )  Stepwise accumulation .

21. Phases of Growth First Radial (Superficial) Later Nodular ( downgrowth ) Histology : Tumor cells grow horizontally & vertically. Loss of nesting pattern ( sheets ) Neoplastic melanocytes are larger and atypical. Large nuclei with prominent nucleoli

22. Clinical Diagnosis : Change in (color, size or shape ), itching or pain , ulceration  for an existing lesion . New pigmented lesion in an adult . Main signs summarized by : ABCDE Asymmetry of shape . Border is irregular. Color is uneven . Diameter is enlarged . Evolution .

23. Mainly depends on : DEPTH OF INVASION Breslow Staging : Depth of invasion in mm . The superficial lesions has a better Px than vertical ones (metastatic rate is higher in vertical). Spread is by lymphatics & blood to any site ( liver,lung , brain ... etc ) Staging & Prognosis