<prompt> Regarding malignant melanoma all the following are true EXCEPTVertical depth of invasion is a prognostic indicatorOccurs in actinic damaged skinLentigo maligna is a type of malignant melanomaMay shows spontaneous regression  <response>: Ans d May shows spontaneous regression Ref: Sabistons textbook of surgery 18th editionRisk factors1. Solar ultraviolet UV radiation - actinic damaged skin2. Severe bums in childhood3. Fair complexion4. Dysplastic nevus DN syndrome5. Xeroderma pigmentosum6. History of nonmelanoma skin cancer NMSC7. Family history of melanoma.Precursor Lesions and Risk Factors1. Congenital nevi2. DNs3. Spitz neviHistologic types of Cutaneous MelanomaSuperficial spreading melanoma - most commonLentigomalignaAcral lentiginous melanomaNodular melanomaPrognostic factors1. LN involvement Most important2. Breslows thickness Major determinant in the absence of nodal disease 