Robbins CH 25 Skin Flashcards
Vesicles
Fluid filled
Max size of 5mm
Easily traumatized and unroofed–leaving shallow ulcerations
Bullae
Fluid filled
> 0.5 cm
Macules
Not raised
Flat area
Patch
flat area > 0.5cm
Papules
Elevated
Nodule
Elevated >0.5 cm
Pustules
Raised and filled with leukocytes to impart a yellow color
A focal increase in melanocytes of the basal layer causing a brown macule whose pigmentation is not related to sun exposure…
Lentigo
What is seen with lentigo?
Tanning of epidermis and elongation of rate ridges
Basal melanocytic hyperplasia
A masklike area of facial hyperpigmenation associated with pregnancy?
Melasma
A collection of mast cells with light brown appearance on skin?
Urticaria pigmentosa
Both junctional and intradermal and shows swirling cell on microscopy?
Melancytic nevus
Uncommon condition with hyper pigmented areas in skin folds–may occur in association with endocrinopathies or with neoplasms?
Acanthosis nigricans
Occurs in sun-exposed skin of adults–the cells have darker nuclei with scant cytoplasm. The sporadic form has PTCH gene mutation?
Basal cell carcinomas
Raised, pigmented lesions of thickened epidermis, seen in older adults. associated with FGFR3 mutation
Seborrheic keratoses
Hundrends of skin lesions that have been forming since childhood. Often seen in two siblings. Dark brown pigmented lesions that occur in sun-exposed and non-sun-exposed areas?
Dysplastic nevus syndrome
Dysplastic nevus syndrome is a precursor of….
Malignant melanoma
What mutation is seen in dysplastic nevus syndrome?
Cyclin-depdendent kinase inhibitor 2 mutations (CDKN2A)
Associated with TSC1 mutation?
Tuberous sclerosis
What type of melanoma is more aggressive and more likely to metastasize?
Melanoma with nodular growth pattern
Exhibits an indolent radial growth phase for many years before reaching an accelerated nodular vertical growth phase. Most lesions on head and neck or older pts. Activating BRAF mutation is seen?
Lentigo maligna melanoma
Dilated sub epidermal blood vessels forming lesions that is associated with ATM mutations?
Ataxia-telangiectasia
Associated with TYP mutation?
Albinism
What does the TYP gene do?
Encodes the enzyme tyrosinase that is part of the initial pathway of melanin production by melanocytes
Defects in DNA excision repair that predisposes pt to skin cancers, such as basal cell carcinoma, squamous cell carcinoma and malignant melanoma?
Xeroderma pigmentosum
Flat, round pigmented sharply demarcated, non-painful, non-ulcerating lesions composed of basaloid cells that commonly occur in older individuals?
Seborrheic keratoses
Rough raised lesion common on hands and feet?
Verruca vulgaris (Wart)
Lesions in axillae and flexural areas. Not painful or pruritic..
Acanthosis nigricans
Involvement of the skin in children that produces reddish papillose or nodules or erythematous scaling plaques?
Langerhans cell histiocytoses
Acrochordon or skin tag composed of a central core of fibrovascular connective tissue covered by normal appearing squamous epithelium?
Fibroepithelial polyp
Forms a red nodule that is composed of vascular spaces in the upper dermis?
Hemangioma
Epithelial cyst that forms on the scalp?
Pilar cyst
Localized dermal collection of lipid-laden macrophages associated with hyperlipidemia?
Xanthoma
Cystic structure formed from downward growth of epithelium or expansion of a hair follicle–lined by squamous epithelium that desquamates keratinaceous debris into the center of the expanding cyst?
Epidermal inclusion cyst
Produces comedones–typically on face and upper trunk?
Acne
Form of a benign adnexal tumor–subcutatneous nodule usually seen on the head, neck, and upper trunk?
Trichoepithelioma
Premalignant lesions associated with sun exposure?
Actinic keratoses
What are the risk factors associated with squamous cell carcinoma?
UV exposure
Scarring from burn injury
Irradiation
Immunosuppression
What is a precursor of squamous cell carcinoma that is a disorder involving DNA repair?
Xeroderma pigmentosum
Hypersensitivity response to infections or drugs causing lesions that have many forms–papules, macules, vesicles, bullae?
Erythema multiforme
Self-limited inflammatory disorder that manifest as purple, pruritic, polygonal papules?
Lichen planus
Inflammatory dermatosis that can be associated with arthritis, myopathy, enteropathy, atherosclerotic heart disease?
Psoriasis
Inherited condition resulting from mutation in one of several XP genes–nucleotide excision repair defect–ind. can develop any of the sun-exposed skin disorders. Child presenting with squamous cell carcinoma?
Xeroderma pigmentosum
Arise as pearly papillose on sun-exposed areas of the skin. Slowly infiltrate surrounding tissues, and gradually enlarge?
Basal cell carcinoma
Premalignant lesion of the epidermis that does not invade surrounding tissue?
Actinic keratosis
Benign lesion of the dermis composed of cells resembling fibroblasts. Localized, dermal, spindle cell proliferation with overlying epidermal hyperplasia and downward elongation of hyper pigmented rate ridges?
Dermatofibroma
Malignant counterpart of dermatofibroma associated with PDGFB gene juxtaposed with the promoter region of COL1A1?
Dermatofibrosarcoma protuberans
What occurs as a result of PDGFB gene juxtaposed with the promoter region of COL1A1 seen withDermatofibrosarcoma protuberans?
Upregulation of a growth-promoting factor
FGFR3 mutations
Seboorheic keratoses
KIT mutations
Mast cell proliferations
PTCH1 mutations
Basal cell carcinoma
TSC1 mutations
Tuberous sclerosis
A localized form of mastocytosis–cutaneous lesions show the characteristic Darier sign on rubbing (more pruritic with swelling and erythema when rubbed)…
Urticaria pigmentosa
Point mutation in KIT oncogene involved where upper dermal infiltrates of large cell with abundant pink cytoplasm that stains an intense purple color with toluidine blue?
Urticaria pigmentosa
Common reaction to many skin irritants?
Aczematous dermatitis
Reaction to a chemical–often a drug
Has systemic effect
Lesions often begin with targetoid appearance…
Erythema multiforme
A hypersensitivity response to certain infections, disorders and drugs can lead to erythema multiforme. What are these infections/drugs/disorders?
Drugs–sulfonamides and penicillin
Infections–HSV, mycoplasma and fungal infections
Disorders–malignant disease and collagen vascular diseases–SLE
Urticaria is a ____
type I hypersensitivity
What is Koebner phenomenon?
Seen with psoriasis–appearance of lesion with trauma
What causes the skin damage seen with psoriasis?
Abnormal CD4+ and CD8+ lymphocyte activation with release of many cytokines
What is seen on biopsy of psoriatic lesion?
thinning of stratum granulosum with marked overlying parakeratotic scale containing micro abscesses
What Th cells are involved in the elaborate cytokine promotion of cell proliferation seen in psoriasis?
Th17 and Th1
What are the nail changes seen with psoriasis?
Yellow-brown discoloration
Pitting
Dimpling
Separation of nail plate from the nail bed (onycholysis)
What are disease associated with Psoriasis?
Arthritis
Myopathy
Enteropathy
Atherosclerotic heart disease
Autoantibodies to desmoglein–causing suprabasal blister fromation?
Pemphigus vulgaris
Pruritic, purple, polygonal papillose with sandlike infiltrate of lymphocytes at the dermal-epidermal junction
Lichen planus
What cell is involved in lichen plans?
CD8+ cells reacting to antigen in the basal layer and dermoepidermal junction
Where is the common spot on the body for lichen planus lesions to form?
Oral lesions
Caused by IgG autoantibodies directed at an intercellular cement substance called desmoglein?
Pemphigus Vulgaris lesions
What are the common sites of intraepidermal blisters to occur with pemphigus vulagaris?
Scalp
Axillae
Groin
Knees
What is seen on biopsy of pemphigus vulgarism lesions?
Epidermal acatholysis and formation of intraepidermal blister
Basal cell layer remains intact
Bullous pemphigoid results from what?
linear IgG deposition at the basal-cell basement membrane attachment plaques (Hemidesmososmes) containing bulls pemphigoid antigen (BPAG)
Subepidermal bullae is formed
Disease associated with celiac disease?
Dermatitis herpetiformis
What is the pathogenesis of dermatitis herpetiformis?
Reticulin–component of the anchoring fibrils that attach the epidermal basement membrane of the superficial dermis are affected by the IgA/IgG antibodies that are formed against the gliadin protein in gluten
What type of reaction is contact dermatitis and where does this happen on body?
Type IV hypersensitivity reaction
Seen on hands and forearms
What type of reaction id discoid lupus erythematous?
Type III hypersensitivity reaction–antigen-antybody complex deposition along the BM of the epidermis
What are the early and late lesions seen with discoid lupus erythematosus?
Early–well-demarcated scaly purple macules or papules
Later– expansion into discoid plaques
What is seen on biopsy of discoid lupus erythematous?
Basal vacuolar degeneration, areas of epidermal atrophy, acanthuses, keratotic follicular plugging, BM thickening, superficial and deep perivascular lymphocytic infiltrates
Bullous pemphigoid lesions involve antibodies against what?
type XVII collagen as a component of hemidesmosomes
Occur at the dermal-epidermal junction
What is the sever form of erythemia multiforme that is mediated by cytotoxic CD8+ cells targeting epidermal basal cells?
Toxic epidermal necrolysis
What organism is involved in acne vulgaris?
Propionibacterium acnes organism
Form of panniculitis that is associated with infections, drug ingestion, inflammatory bowel disease, and malignancies. The inflammation primarily involves dermal adipose tissue?
Erythema Nodosum
Seen on the face and hands with crusting lesions. Caused by staphylococcus aureus and B-hemolytic streptococcal infections. Subcorneal pustules.
Impetigo
Firm nodules that microscopically contain pink cytoplasmic inclusions?
Molluscum contagiosum lesions–molluscum bodies are the pink inclusions
BRAF mutations
Present in melanocytic proliferations–dysplastic nevi
IgA deposition
Dermatitis herpetiformis
Type IV hypersensitivity reaction of the skin?
Contact dermatitis
Poxvirus
Molluscum contagiosum
Superficial infection of the skin that produces shallow erosions– honey colored crust
Coagulase-postive staphylococcus aures or group A B-hemolytic streptococcus
Lesions are highly infections
Impetigo
Common disorder resulting from superficial dermatophyte infection by various fungal species –trichophyton, epidermophyton, and microsporum?
Athlete’s foot–tinea pedis
What are the fungal species involved in athlete’s foot–tinea pedis?
Trichophyton
Epidermophyton
Microsporum
Mites burrow through the stratum cornerum–producing linear lesions–intense pruritus?
Sarcoptes scabiei
Localized firm nodule caused by poxvirus?
Molluscum contagiosum
Superficial dermatophytic fungal infection that produces erythema and crusting–annular appearance with central clearing–Ring-worm?
Tinea corporis
Common condition caused by a superficial fungal infection–malassezia furfur with lesions that wax and wane. No pain/itching or bleeding involved?
Tinea versicolor
Cause of Hansen disease–manifest with areas of skin anesthesia that predispose to repeated trauma?
Mycobacterium leprae
