Malignant melanoma- risk factors (continued)

1. Malignant melanoma- risk factors (continued) • Familial melanoma (10-15% of patients) • Dysplastic nevi • Large congenital nevi- about 6% develop MM

2. Clinical appearance • ABCD criteria: Asymmetry Border irregularity Color variation Diameter->6mm

5. Growth patterns • Radial growth: • Tendency of melanoma to grow horizontally within the epidermis and superficial dermis, often for a prolonged time. • During this stage ,melonoma cells do not have capacity to metastasize • lentigo maligna, • superficial spreading and • acral/mucosal lentiginous

6. Vertical growth • The melanoma cells grows downwards into deeper dermal layers • This event is clinically marked by the development of a nodule in a relatively flat radial growth lesion • Develops capacity to metastasize

7. Clinicopathologic types of Malignant melanoma • Lentigo maligna: -Sun-exposed areas of elderly white patients, usually the face -Flat, slow-growing, prolonged in situ phase (ABCD criteria) -Proliferation of atypical melanocytes along the basal layer

11. Superficial spreading melanoma • The most common type of melanoma (70%) • Most commonly diagnosed in the fourth and fifth decades • Can occur in any location but more in intermittently exposed skin • Macroscopic-ABCD criteria apply • Nodule appearance- usually implies deep invasion • Microscopically- uniform atypical melanocytes, single and nesting

15. Acral lentiginous melanoma • Appears on the palms, soles and subungual areas • Diagnosed in older age groups • More common in black and oriental people • 10% of melanoma

18. Nodular melanoma • Represents about 15% of melanomas • Can affect all body surfaces, mainly the trunk, head and neck • Associated with short duration before diagnosis • ABCD criteria do not apply: can present as well-circumscribed smooth nodule in normal skin or in a nevus

21. Microscopy: • Cells are arranged in the form of poorly formed nests or nodules • The individual melanoma cells are • Large cells • Large irregular nuclei • Prominent red eosinophilic nucleoli

24. Laboratory methods • Melanin stains- Fontana-Masson • Immunohistochemistry- S-100 protein- HMB-45- more specific,

26. Spread and metastases • Epidermis to papillary dermis, reticular dermis and subcutaneous fat • Regional lymph node metastases are highly predictive of visceral metastases • Distant metastases- liver, lungs, gastrointestinal tract, bone, CNS

27. Staging • Tumor thickness (Breslow’s system)- most important prognostic factor. Measured from the top of the granular layer/ulcer base to the deepest tumor cell -Stage I:Less than 1mm- -Stage II:Between 1to 2mm- -Stage III:Between 2 to 4mm- -Stage IV:Over 4mm-

28. Prognostic factors (continued)-Level of invasion • Clark’s system: 5y survival level I- intraepidermal (in situ) 100% level II- in the papillary dermis 100% level III- filling the papillary dermis 88% level IV- in the reticular dermis 66% level V- in the subcutaneous fat 15% • Level of invasion has a significant impact on survival

34. Prognostic factors- continued • Ulceration- the second most important prognostic determinator of the primary tumor- bad prognosis • Mitotic activity- relationship between mitotic activity and prognosis: high mitotic rate associated with a bad prognosis

35. Good Luck!……..