pigmented legions Flashcards
what do melanocytes convert to make pigment
tyrosine
what gene is responsible for pigment and how
MC1R converts phaeomelanin (red/ light)–> eumelanin (dark/ brown)
what do defects in MC1R cause
1 defective MC1R causes freckling, 2 causes red hair
what are ephilides and when do they normally occur
freckles, in the sun
what are atinic/ solar lentiges and what causes them and are they cancerous
flat, macular areas of pigment in UV exposed areas (sunspots/ sign of skin ageing) from an increase in melanin and basal melanocytes, non cancerous
what are seborrheic keratosis
AKA basal cell papilloma, look like stuck on cocopop and a sign of ageing skin
how do seborrheic keratoses form
benign proliferation of epidermal keratinocytes. epidermal acanthosis, hyperkeratosis and horn cysts
what are melanocytic naevi and what types are there
congenital or acquired birth mark.
common: usual, dysplastic, rare: halo, blue, spitz
what is a usual. type melanocytic naevi
very common benign legions (moles), V low malignant potenial. junctional (DEJ) –> compound –> dermal
what is a dysplastic naevi
unusual mole, >6mm, variation in pigment, asymmetrical
what is sporadic type dysplastic naevi
not inherited, increased risk of MM
what is familial type dysplastic naevi
strong FH of melanoma, autosomal inheritance, lots of atypical naevi and lifetime risk of MM
what is a halo naevi
peripheral halo of depigmentation from lymphocytic attack
what is a blue naevi
entirely dermal, pigment rich dendritic cell, mimic melanoma
what is a spitz naevi
mostly benign, aged usually under 20, small, pink, well defined
