Pathoma - 19 (Skin Part 2)

eliot2014's version from 2016-01-22 04:15

Section 1

Question Answer
In what cells is melanin made?melanocytes
What layer are melanocytes located?basal layer of epidermis
In what organelle is melanin made? In what cell are these organelles contained?Melanin is made in melanosomes. Melanosomes are contained in melanocytes.
From what germ layer are melanocytes derived?neural crest
What is the precursor molecule for melanin?Tyrosine
Melaonsomes pass melanin to which cells?keratinocytes
What is vitiligo?autoimmune destruction of melanocytes
What is the most common enzyme deficiency that causes albinism?tyrosinase
Albinism increases risk forSCC, BCC, and melanoma due to reduced protection against UVB
Whats another name for "ephelis" ?freckle
why are freckles dark?increased number of MELANOSOMES (NOT melanocytes!!)
what is a mole/nevusbenign proliferation of MELANOCYTES
what is the precursor of melanoma?dysplastic nevus
What is melasma?mask-like hyperpigmentation of cheeks
What is melasma associated with?pregnancy and OCP use
Dark spot on skin with hair?congenital nevus (mole) not melanoma (melanoma would not have hair)
Acquired nevus begins in which skin layer?at the dermal-epidermal junction.
What is the most common mole in children?acquired nevus, present at the dermal-epidermal junction
From what layer and into what layer does a compound nevus grow? What does it eventually turn into?it grows by extension from the dermal-epidermal junction in to the dermis. the junctional component is eventually lost, resulting in an intradermal nevus
malignant neoplasm of melanocytesmelanoma
Risk factors for melanomaUVB induced DNA damage and prolonged exposure to sunlight, albinism, xeroderma pigmentosum, dysplastic nevus syndrome
Dysplastic nevus syndrome--AD or AR? What cancer does it predispose to?AD; Melanoma
What are the ABCDE of melanoma?Asymmetry, Borders are irregular, Color is not uniform, Diameter is greater than 6 mm, Evolving
hair growing on nevus or melanoma?nevus! shows that melanocytes are respecting hair follcies
diameter size for melanoma?diameter >6mm
What are the two growth phases of melanoma? What is the risk of metastasis with each?Radial growth horizontally along the epidermis and superficial dermis (low risk of metastasis); Vertical growth into the deep dermis (increased risk of mets)
What is the most important prognostic factor predicting metastasis of melanoma?Breslow thickness (depth of extension)
What is the most common melanoma variant?Superficial spreading. Dominant early radial growth. Good prognosis
What is lentigo maligna melanoma?Lentiginous proliferation (remains along the epidermal-dermal junction). Radial growth. Good prognosis
Which form of melanoma has the worst prognosis?Nodular. Early vertical growth. Poor prognosis
most common cause of death from skin cancer?melanoma
What are the 4 variants of melanoma?Superficial spreading, Lentigo meligna melanoma, Nodular, and Acral lentiginous
which melanoma variant arises on palms or soles in dark skinned ptsAcral Lentiginous (melanoma) --> NOT related to UV LIGHT
"acral" means involving what 2 locationspalms and soles

Section 2

Question Answer
What is impetigo and what causes it?superficial bacterial skin infection (s. aureus and s. pyogenes)
What group is commonly affected by impetigo?children
How does impetigo present?erythematous macules that progress to pustules. pustuls rupture and result in erosions and dry, crusted, honely-colored serum.
Where is impetigo usually located?face
What is cellulitis and what cuases it?deeper (dermal and subcutaneous) infection. S. aureus and s. pyogenes
How does cellulitis present?red, tender, swollen rash with fever.
Risk factors for cellulitis?surgery, trauma, insect bite
What is a feared complication of cellulitis?necrotizing fasciitis
Describe necrotizing fasciitis (appearance, cause etc)necrosis of subcutaenous tissues due to infection with anaerobic flesh eating bacteria. production of co2 causes crepitus. surgical emergency
Which toxins causes staph scalded skin syndrome?s. aureus exfoliative toxin A and B toxins --> results in epidermolysis of STRATUM GRANULOSUM
Where does separation occur in toxic epidermal necrolysis?dermal epidermal junction (unlike scalded skin syndrome, in which the stratum granulosum separates from the other layers)
Where does the separation occur in staph scalded skin syndrome?separates stratum granulosum from rest of skin
flesh colored papule with rough surfaceverruca = wart
What virus causes warts?HPV
What cells does HPV infect (that eventually lead to warts)?keratinocytes, characterized by koilocytic change
What are common locations of warts?hands and feet
firm pink umbilicated papules due to poxvirusmolluscum contagiosum
what cells are infected by poxvirus and what changes do they have?keratinocytes; have cytoplasmic inclusion bodies
What demographics are commonly affected by molluscum contagiosum?children, sexually active adults, immunocompromised
what are the worse versions of erythema multiforme?Erythema multiforme --> steven johnsons syndrome --> toxic epidermal necrolysis