Term
| What is unique about the melanocytes' cytostructure? |
|
Definition
| They have perfectly round nuclei |
|
|
Term
| In addition to manufacturing hair shafts, what else are hair follicles capable of doing? |
|
Definition
| harbor epithelial stem cells capable of regenerating superficial epithelial skin structures |
|
|
Term
| Where are the Merkel cells and Meissner corpuscles located, respectively? |
|
Definition
| w/in the epithelial basal cell layer/ in the papillary dermis |
|
|
Term
| What is lichenification and why does it occur? |
|
Definition
| It is the diffuse thickening of the epidermis with resultingg accentuation of skin lines. It occurs from intense, chronic rubbing. |
|
|
Term
| In which disease do we see marked acanthosis? |
|
Definition
| lichen simplex chronicus (often due to chronic irritation) |
|
|
Term
| What is the difference between pemphigus vulgaris and bullous pemphigoid? |
|
Definition
| The former deals with autoantibodies to intercellular keratinocyte connections. The latter deals with autoantibodies to dermoepidermal junction antigens. |
|
|
Term
| Dyskeratosis, the abnormal premature keratinization below the stratum granulum, typically occurs as a result of what? |
|
Definition
|
|
Term
|
Definition
| Influx of inflammatory cells into the epidermis (spongiosis- intercellular edema of the epidermis) |
|
|
Term
| What is hyperkeratosis, and what disease features such change? |
|
Definition
| hyperplasia of the stratum corneum/ find this in ichthyosis |
|
|
Term
|
Definition
| hyperplasia and enlargement of contiguous dermal papillae |
|
|
Term
| What's the genetic basis of oculocutaneous albinism, and what are associating presentations? |
|
Definition
| AR, skin malignancies risk increased |
|
|
Term
| In addition to non-nested (linear) melanocytic hyperplasia, what else is commonly found in a lentigo? |
|
Definition
|
|
Term
| What are the genetic variations that are associated with nevi being neoplasms? |
|
Definition
| mutations in BRAF or NRAS follwed by defect in p16/INk4a which normally arrests cyclin-dependent kinases |
|
|
Term
| What the basis behind the strong dark coloration of a blue nevus? |
|
Definition
| The melanocytes are deep down in the dermis, so that light gets poorly refracted |
|
|
Term
| Clinically, what is a spitz nevus often confused with? |
|
Definition
|
|
Term
| What are the cytologic features of Spitz nevus? |
|
Definition
| large, plump cells with pink-blue cytoplasm, spindle-shaped cells, pagetoid nefts and clefts around the nests |
|
|
Term
| In a halo nevus, why is there lightening of the skin around the nevus? |
|
Definition
| Because the infiltrating lymphocytes respond not only against nevus cells but also against surrounding normal melanocytes |
|
|
Term
| In dysplastic nevi, what is characteristic of the nevus cell nests? |
|
Definition
| They may be enlarged and oftne fuse or coalesce with adjacent nests/ begin to replace the normal basal cell layer along the dermoepidermal junction |
|
|
Term
| For a dysplastic nevus with cytologic atypia, what is occurring in the dermis? |
|
Definition
| There is linear/lamellar fibrosis (bridging fibrosis) |
|
|
Term
| In autosomal dominant dysplastic nevus syndrome, what are the two common mutations found? |
|
Definition
| mutated genes in CDKN2A and CDK4 |
|
|
Term
| What does radial growth refer to? |
|
Definition
| horizontal spread of melanoma within the epidermis and superficial dermis |
|
|
Term
| In Lentigo Maligna, how does it usually present? |
|
Definition
| as an indolent lesion on the fae of older men that may remain in the radial growth phase for several decades |
|
|
Term
| How do you measure the Breslow Depth of Invasion? |
|
Definition
| from the granular cell layer to the base of the tumor |
|
|
Term
| For gauging the prognosis of a melanoma, at what depth above and below do we measure? |
|
Definition
|
|
Term
| What are the 5 levels of invasion according to Clark? |
|
Definition
| Intraepidermal, Papillary, Papillary-Reticular, Reticular, and Subcutaneous |
|
|
Term
| Seborrheic Keratoses in people of color may manifest as color, multiple small lesions on the face? |
|
Definition
| Dermatosis papulosa nigra |
|
|
Term
| What is an association with Seborrheic Keratosis that does not involve the skin? |
|
Definition
| paraneoplastic syndrome- Leser Trelat |
|
|
Term
| Describe the appearance of the seborrheic keratosis? |
|
Definition
| well-demarcated coinlike pigmented lesion containing dark keratin-filled surface plugs |
|
|
Term
| What type of cysts are associated with seborrheic keratosis? |
|
Definition
| invagination and horn cysts |
|
|
Term
| Acanthosis Nigricans in adults can be a sign of what? |
|
Definition
|
|
Term
| Fibroepithelial polyp has a rare association with Birt-Hogg-Dube syndrome, which features what? |
|
Definition
| follicular lesions, kidney tumors, and pulmonary cysts |
|
|
Term
| What is an epithelial cyst typically filled with? |
|
Definition
| keratin and lipid-containing debris from sebaceous secretions |
|
|
Term
| What is unique about the pilar/trichilemmal cysts interms of their structure? |
|
Definition
| They lack a granular cell layer |
|
|
Term
| Where are pilar/trichilemmal cysts typically find? |
|
Definition
|
|
Term
| Trichilemmomas are typically featured in what syndrome? |
|
Definition
|
|
Term
| In sebaceous adenoma, what two cell populations are increased? What syndrome is sebaceous adenoma commonly linked to? |
|
Definition
| both sebocytesa and increased peripheral basaloid cells are prominent/ commonly linked to Muir-Torre sydrome, which also features HNPCC |
|
|
Term
| Squamous cell carcinoma commonly manifests as what? |
|
Definition
| sharply defined, red scaling plaques |
|
|
Term
| In the pathogenesis of SCC, what mutation is common? |
|
Definition
| p53, leading to loss G1 growth arrests and DNA repair |
|
|
Term
| In nevoid BCC syndrome, what happens as a result of the PTCH gene defect |
|
Definition
| causes uninhibited activation of SMO leading to BCC |
|
|
Term
| What distinguishes a benign fibrous histiocytoma from a malignant one? |
|
Definition
| Benign ones are factor XIIIa positive and CD34 negative |
|
|
Term
| In whom and on where does benign fibrous histiocytoma (dermatofibroma) occur? |
|
Definition
| on the legs of young-to-middle aged women |
|
|
Term
| Upon lateral compression, what happens to the dermatofibroma? |
|
Definition
|
|
Term
| What are some histologic features of dermatofibroma? |
|
Definition
| overlying epidermal hyperplasia and entrapped collagen bundles |
|
|
Term
| What is the molecular hallmark of dermatofibrosarcoma protuberans? |
|
Definition
| balanced translocation between COL1A1 and PDGF Beta--> leading to overexpression of PDGF Beta (treat with TK inhibitor) |
|
|
Term
| Name two histologic features of dermatofibrosarcoma protuberans? |
|
Definition
(1) invasion leading to trapping of fat and honeycombed appearance
(2) fibroblasts have radial arrangement- storiform pattern (like a pinwheel) |
|
|
Term
| In Sturge Weber syndrome, whom do we typically target for suspicion? |
|
Definition
| child with a large facial port-wine stain, seizures, and mental deficiency (stain a form of vascular ectasia) |
|
|
Term
| Mycosis fungoides may be confused with psoriasis for what reason? |
|
Definition
| it presents as raised, scaling plaques just like psoriasis |
|
|
Term
| In mycosis fungoides, what clusters are located in the epidermis? |
|
Definition
| T-helper cell aggregate bands called Pautrier microabscesses |
|
|
Term
| In sezary syndrome, there are the features of Mycosis Fungoides plus what else? |
|
Definition
| blood involvement leading to diffuse erythema and scaling |
|
|
Term
| A localized form of mastocytosis is known as what? how does it present? |
|
Definition
| urticaria pigmentosa/ lesions are round to oval, red-brown, nonscaling papules and small plaques |
|
|
Term
|
Definition
| related to mastocytosis; area of dermal edema and erythea (wheal) in response to rubbing |
|
|
Term
| What's the pathogenesis of Mastocytosis and how do we use that information to treat the disease? |
|
Definition
| there are acquired activating point mutations in the c-KIT receptor tyrosine kinase leading to constitutive activation so we try to block that |
|
|
Term
| In acute inflammatory dermatoses what cell population is not present, surprisingly? |
|
Definition
|
|
Term
| In urticaria, what's happening to the dermis? |
|
Definition
| there is edema formation with scattered eosinophils/neutrophils and dilated vascular spaces |
|
|
Term
| In acute eczematous dermatitis, what do the lesions look like? |
|
Definition
| red, papulovesicular, oozing, crusted lesions |
|
|
Term
| Spongiosis with intraepithelial vesicle formation occurs in what disease? |
|
Definition
| Allergic contact dermatitis |
|
|
Term
| In erythema multiforme, what is special about the location of the lesions? |
|
Definition
| they frequently are widely distributed, and there is symmetric involvement of the extremities |
|
|
Term
| What is the apperance of the lesion in erythema multiforme? |
|
Definition
|
|
Term
| Accumulation of lymphocytes along the DEJ, intimate association with degenerating and necrotic keratinocytes is associated with with what disease? |
|
Definition
|
|
Term
| What are two variants of Erythema multiforme that can be damaging? |
|
Definition
| Stevens Johnson Syndrome and toxic epidermal necrolysis |
|
|
Term
| In psoriasis, what happens to the stratum granulosum? |
|
Definition
| it becomes thinned/absent, with increased cell turnover and an extensive overlying parakeratotic scale |
|
|
Term
| Accumulations of neutrophils in the stratum corneum are known as what in Psoriasis? |
|
Definition
|
|
Term
| With what genotype does psoriasis have a strong association? |
|
Definition
|
|
Term
| What organism may have a possible role in seborrheic dermatitis? |
|
Definition
|
|
Term
| What is known about the histologic features of seborrheic dermatitis? |
|
Definition
| they share features with both spongiotic dermatitis and psoriasis |
|
|
Term
| The Wickham striae in Lichen planus that highlight the papules are due to what? |
|
Definition
|
|
Term
| In the dermoepidermal junction, what do we see in Lichen planus? |
|
Definition
| we see band-like infiltrates of lymphocytes at the DEJ, pointed rete ridges due to chronic basal cell layer injury by lymphocytes, and colloid/civatte bodies (anucleate, necrotic basal cells) incorporated into the inflamed papillary dermis |
|
|
Term
| What does IF of lupus reveal? |
|
Definition
| granular band of IgG and C3 at the DEJ |
|
|
Term
| What is icthyosis due to and what does it mean when it is acquired in adulthood? |
|
Definition
| It is due to defective desquamation and can signify lymphocytic or visceral malignancies when acquired in adults |
|
|
Term
| What happens to the stratum corneum in Ichthyosis? |
|
Definition
| it loses its basket weaving pattner- just parallel strips |
|
|
Term
| What's an example of a suprabasal blister? |
|
Definition
|
|
Term
| What is the appearance of the vesicles in Pemphigus? |
|
Definition
| They are flaccid and accompanied by bullae and crust |
|
|
Term
| What sort of inflammatory cells do we predominantly see in pemphigus vulgaris? |
|
Definition
|
|
Term
| In pemphigus folliaceous, what is rarely affected? |
|
Definition
|
|
Term
| In Pemphigus IF, what is the pattern of the Ig deposition? |
|
Definition
|
|
Term
| In bullous pemphigoids, what is the condition of the bullae? |
|
Definition
| they are tense and do not rupture easily |
|
|
Term
| In bullous pemphigoids, what are the blisters filled with? |
|
Definition
| mostly eosinophils and some lymphocytes assocatied with basal cell layer destruction and the creation of the subepidermal cleft |
|
|
Term
| In bullous pemphigoid, what is present along the DEJ? |
|
Definition
| there is basal vacuolization |
|
|
Term
| What causes DEJ separation in bullous pemphigoids? |
|
Definition
| When there is antibody binding to BPAG2 in the lamina lucida of the basement membrane, that activates complements and there is recruitment of eosinophil peroxidase and neutrophilic proteases. |
|
|
Term
| In dermatitis herpetiformis, what do the IgA autoantibodies bind to? |
|
Definition
| fibrils that anchor hemidesmosomes to dermis |
|
|
Term
| In Dermatitis Herpetiformis, where are the IgA deposits typically located? |
|
Definition
| at the tips of the Dermal Papillae |
|
|
Term
| What is the basis for epidermolysis bullosa? |
|
Definition
| there are inherited defects in structural proteins that stabilize desmosomes or hemidesmosomes |
|
|
Term
| In the simplex form of EB, what is the genetic basis? |
|
Definition
| there are mutations in the genes encoding keratins |
|
|
Term
| In the dystrophica type of EB, where are the genetic defects? |
|
Definition
|
|
Term
| How is recessive EB different from AD EB? |
|
Definition
| it is more severe, there are scars and deformities of the teeth |
|
|
Term
| In porphyria, what are the primary alterations detected by light microscopy? |
|
Definition
| there is subepidermal blistering and marked thickening of the walls of superficial blood vessels |
|
|
Term
| In rosacea, there are high levels of what? |
|
Definition
| cathelicidn (endogenous antimicrobial peptide in high levels) |
|
|
Term
In panniclitis, there is inflammatory reaction that affects what two sources? |
|
Definition
| connective tissue septa separating fat lobules or the fat lobules themselves |
|
|
Term
| In which type of panniculitis is there vasculitis? |
|
Definition
| erythema induratum--> granulomatous inflammation and zones of caseous necrosis involving the fat lobbule/ necrotizing vasculitis |
|
|
Term
| Name two histologic features of verruca vulgaris? |
|
Definition
| hypergranulosis with keratohyaline granules and koilocytic changes |
|
|
Term
| What is the unique feature of molluscum contagiosum papules? |
|
Definition
| They have central umbilication |
|
|
Term
| What is the general apperance of the lesion in a superficial fungal infection? |
|
Definition
| annular lesion with central clearing and fine peripheral scale |
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