case studies Flashcards
What is the Luxol-fast blue stain used for?
It stains normal myelin blue
What does it mean when there is no cellular infiltrate in an MS plaque?
It is a chrnic plaque and demyelination occured a long time ago
what is a sevier-munger stain used for?
it highlights axonal processes, which are visible as black threadline structues
- axonal preservation is present in some plaques despite loss of myelin
what is an important inflmmatiory mediator in the plaques of MS?
macrophages because the phagocytize lipid rich myelin debris
what disease causes symmetrical myelin injury and spating of subcortical U fibers?
leukodystrophy
metachromic leukodystrophy
arylsulfatase A deficiency
Krabbe disease
glactocerebroside b-galactosidase deficiency
arenoleukodytrophy
defect in peroxisomal membrane associted protein
what is Wallerian degeneration?
a type of axonal degeneration in which axons degenerate in response to more proximal nerve injury (transection injury)
what is primary axonal degeneration?
type of axonal degeneration that begins in the most distal portion of the axon and progresses in a proximal fashon (loss of sensation in a stocking glove pattern)
myelin ovoids
degenerating axons and fragments of myelin characteristic feature of axonal peripheral neuropathies
what place is common for a schwannoma?
CN VII AKA acoustic neuroma
what are verocay bodies?
the neopastic nuclei of a schwanoma line up in irregular palisades
what neoplasm are associted wuth Antoni A and Antoni B
schwanomas
what cells are in the stratum basle?
keratinocytes, melanocytes, and merkel cell
what is in the stratum germinativum?
germ/stem cells to make the keratinocytes
what is in the stratum spinosum?
new keratinocytes and desmosomes
what is is the stratum granulosum?
granular layer with protein rich keratohylanie granules
what is in the stratum lucidem?
keratinocyes
what is in the stratum corneum?
anucleated cells with keratin
what is a keratinocye?
specialized epithelias cell that has both basal cells and squamous cells `
where are merkel cells present?
specialized regions: lips, oral cavity, palmar skin
associated with terminal neuronal axon
where are the greatest number of ecccrine glands?
chest
face
back
what is the job of eccrine glands?
regulate body temp
where are appocrine sweat glands?
axillae, face, abdomen, genital, scalp
what is in the papillary layer of the dermis?
loose conective tissue right beneath the epidermis
what is in the reticular later of the dermis?
dense dermal collagen/ much thicker and fibrotic
what is a becker nevus and what should you not confuse it with?
it is a solitary lesion that beaks up into smaller macules at the periphery
dont confuse with cafe au lait
what is the tyndall effect?
blue color due to scattering of shorter wavelengths by dermal melanin
what is a nevus of Ota vs Ito
ota- trigeminal nerve 1st and 2nd divisions
Ito- posterior supraclavicular and lateral brachiocutaneous nerves
what is a benign nevus?
a nevus that does not mature, it stays at the dermal epidermal junction
what 2 mutations are associated with dysplastic nevi syndrome?
P16 (CDKN2A) or CDK4
CDK4- resistant to being turned off by P16
P16- can’t block proliferation
- both cause uncontrolled proliferation
what is the inheritance pattern in dysplastic nevi syndrome?
anutosomal dominant
what is prognosis for malignant melonoma 100% related to?
vertical growth/breslows thickening and TNM
lentigo maligna
indolent, usually on the face, seen in elderly
does not spread rapidly
superficial spreading
most commom
seen in sun exposed areas
acral/mucosal lentiginouse
unrelated to sun exposure, in anogenital regions
what is considered a good prognosis in breslow depth?
< 1.7 mm
what is clark’s levels?
10 yr survival based on border
what gene mutations predispose an individual to malignant melonoma?
CDKN2A (P16) allows for no turning off of proliferation
mutated in 40% of familial melonoma
aberrant increaes in RAS and P13/AKT signanling
what 3 tummor suppressors does P16 code for? why is that importaint?
P15/INK4b
P16/INK4a- normally enhances activity og TSGs of Rb family inhibiting CDK4
P14/ARF- enhances activity of p53 by inhibiting activity og MDM2
* all play a role in suppressing proloferation, if mutated cells can grow with no control
what are the gene mutations associated with fair skinned individuals?
MCIR- melanocortin 1 receptor
ASLP-regulation of melanocortin rc signaling
TYR-tyrosine enzyme mutation
dermatosis papulosa nigra
a type of seborrheic keratosis, but with multiple small lesions on the face
what gene mutation is assocted with seborrheic keratosis?
FGFR3 gene- fibroblast growth factor rc gene
what is paraneoplastic syndrome?
when seborrheic keratosis occurd explosivly in large numbers
results from a growing tumor
it is called the leser-Trelat sign and is due to stimulation of transforming growth factor alpha from GI carcinoma
what are the genes associated with bening appendage tumors? why imp?
TSG and PTEN because it can predispose ot internal malignancy
what us Muir Torre syndrome and what is is associted with?
a subset of heredity nonpolyposis carcinoma syndrome associated with sabaceous adenomas that can convert into adenomas
actinic chelitis
keratosis of the lip
impuimod
medication to stimulate the immune system byt stimulating toll like rcs before it turns into SCC
-used in actinic keratosis
what is bowen’s disease?
SCC in situ- no invasion on the dermatoepidermal junction
shaply defined red scaly plaques
involves all layers of the epidermis
what strain of HPV are associated with SCC?
5 and 8
what are the 2 patterns of BCC?
- multifocal growths-originate in epidermis, extend several square cm
- nodular lesions-grow down into dermis, originate in follicular epithelium
what is nevoid BCC syndrome and what gene muattions are associted?
gorlin syndrome, autosomal dominant chr9 PTCH mutations
what does PTCH encode for?
a rc for sonic hedgehog gene, absence of PTCH causes activation of SMO, which leads to BCC
what other conditions is NBCC associted with?
medulloblastomas and ovarian fibromas
What is Non NBCC?
still has a genertic component
30% have PTCH mutations
40-60% have p53 mutations
xeroderma pigmentosa has both PTCH and p53 mutations- doblue wammy for developing lesions ( constant proliferation and increased survival)
