Pathology Flashcards
Localised overgrowth of blood vessels in the dermis =
Haemangiomas causes a port wine stain
melanoblasts migrate from neural crest to ++_
skin
uveal tract
leptomeninges
gene that determines balance of pigment in skin and hair
MC1R (melanocortin 1 receptor)
MC1R turns __ to __melanin
phaeo to eu
hair colour caused by phaeomelanin
red
1 defect in MC1R =
2 defects =
freckles
red hair and freckles
ephilides
freckles - patchy increase in melanin pigmentation
actinic/solar lentigines
age/liver spots
increased melanin and basal melanocytes
face, forearms and dorsal hands
elongated rete ridges in epidermis
acquired naevi in childhood = junctional naevus -
melanocytes proliferate and cluster at DEJ
acquired naevi in adolescence = compound naevus -
junctional clusters and groups of melanocytes in dermis
acquired naevi in adults = intradermal naevus -
no junctional activity, entirely dermal
dysplastic naevi 2 types =
increase in melanoma risk
sporadic - slight risk increase
familial - 100% increase risk
dysplastic naevi histological findings
architectuarl and cellular atypia
host-reaction inflam and fibrosis
epidermis not effaced (unlike melanoma)
characteristics of halo naevi
peripheral depigmented halo
inflammatory regression and overrun by lymphocytes
Blue skin pigmentation is caused by
brown deep in skin scatters light
blue naevi characteristics
entirely dermal and consist of pigment rich dendritic spindle cells.
Characteristics of spitz naevi
in <20yos
large spindle +/epithelioid cells
most entirely benign
rare sites for malignant melanoma
oesophagus meninges eye biliary tract anus
Radial growth phase of melanoma =
macules grow either entirely in situ or with dermal microinvasion
Vertical growth phase of melanoma =
invade dermis with formation of expansile mass with mitoses
only VGP metastasise
melanomas that have a radial and vertical growth phase (RGP and VGP)
superficial spreading
acral/mucosal lentiginous
lentigo maligna
melanoma type that only has a VGP (vertical growth phase)
nodular
common site of nodular melanoma
grows quickly in __ causing __ to stretch thin
trunk
dermis
epidermis stretched thin
suffix b added to staging of melanoma -
ulceration
If have advanced melanoma which is difficult to treat with Sx alone =
chemo, immunotherapy or gene therapy
C-kit mutations are usually in ___ melanomas
Rx -
acral
imatinib
melanomas on intermittently sun-exposed areas have __ mutation
Rx -
BRAF
dabrafenib + vemurafenib (combo with a MEK inhibitor)
benign melanocytic lesions (3)
ephilides (freckles)
lentigines (macule)
naevi
classification of congenital melanocytic naevi by size
small <1.5cm diameter
medium 1.5-19.9cm
large 20+cm
congenital naevi characteristics that are different from acquired
larger
slightly raised
more rugose and elevated as they age
neoplastic melanocytes along the basal layer with can become invasive
usually on ace of elderly with sun damage =
lentigo maligna melanoma
macule with irregular border and colour which has a slow RGP and rapid VGP (develops nodule)
superficial spreading melanoma
blue-black/red-skin coloured nodule which may be ulcerated/bleed and develops rapidly over months
no surrounding macular pigmentation =
nodular melanoma
Hutchinson sign =
in ___
pigmented extension into nail fold
acral lentiginous melanoma
multiple black/brown greasy “stuck-on” lesions often on trunk with a regular border
seborrheic keratoses
Rx for seborrheic keratoses
reassure
freeze
curette
firm nodule of dermal connective tissue, brown/grey
may be caused by insect bites
reassure and excise
dermatofibroma
talon noir =
subcorneal haematoma = black heel
due to trauma
