Dermatopathology Flashcards
Skin
Epidermis = Stratified keratinocytes
-Stratum corneum (Pink keratin in anucleate cells)
-Stratum granulosum (With granules)
-Stratum spinosum (Desmosomes)
-Stratum basalis (Stem cells)
Basement membrane (Hemidesmosomes)
Dermis
Atopic Dermatitis (Eczema)
HSR 1 with pruritic, ery, oozing rash with vesicles and edema
FACE & FLEXOR surfaces
+Asthma, allergic rhinitis
Topical steroid
Contact Dermatitis
Pruritic, ery, oozing rash with vesicles and edema
Upon exposure to allergen or irritant
-Poison ivy, nickel jewelry (Type 4 HSR)
-Detergents
-Drugs, ie PCN
Remove offending agent
Topical steroid
Acne Vulgaris
Comedones, pustules, nodules
Chronic inflammation of follicles & sebaceous glands
-Hormone-increase in sebum
-Excess keratin blocks follicles
-Forms comedones
P. acnes
-Causes inflammation
-Forms pustules or nodules
BP (Antimicrobial)
Vit A (Decrease keratin prouced)
Psoriasis
Well-circumscribed, salmon colored plaques with silvery scale
SCALP & EXTENSOR surfaces, pitting nails
Due to excessive keratinocyte proliferation
Possibly autoimmune (HLA-C & triggered by trauma)
Steroids
Immune-modulating therapy
UVA light with psoralen (PUVA)
Lichen Planus
Pruritic, planar, polygonal, purple papules
+Reticular white lines, Wickham striae
Oral mucosa, elbows, wrists
Associated with chronic hep C infection, but etiology unknown
Pemphigus Vulgaris
Autoimmune destruction of desmosomes; IgG against desmoglein
Acantholysis of stratum spinosum
“Tombstone appearance”
Bullae rupture easily
Skin & oral mucosa
Bullous Pemphigoid
Autoimmune destruction of hemidesmosomes; IgG against basement membrane
Supepidermal blisters, bullae do NOT rupture easily
Oral mucosa is spared
Dermatitis Herpetiformis
Autoimmune deposition of IgA at tips of dermal papillae
Pruritic vesicles and bullae in groups, resembling HSV
Seen in celiac disease
Erythema Multiforme
HSR with targetoid rash & bullae
~HSV infection
Steven-Johnson Syndrome (SJS)
-Skin + oral mucosa + fever
Toxic Epidermal Necrolysis (TEN)
-Diffuse sloughing of skin, resembling SSS
-Adverse drug rxn
-Medical emergency!
Seborrheic Keratosis
Benign proliferation of SQ cells with pseudocysts
Classic “stuck-on” appearance
Common in elderly
Leser-Trelat Sign
-Sudden onset of mulitple SK’s
-Underlying carcinoma of GIT
Acanthosis Nigricans
Epidermal hyperplasia with darkening of skin, “velvet-like” skin
Axilla, groin
Seen in insulin resistance or malignancy
Basal Cell Carcinoma
Malignant proliferation of stratum basalis
Especially on UPPER lip
“Peripheral palisating” ***
Surgical excision
Risk: Prolonged exposure to sunlight, albinism, xeroderma pigmentosum
Squamous Cell Carcinoma
Malignant proliferation of SQ cells
Ulcerated, nodular
LOWER lip
Surgical excision
Risk: Same as BCC’s
+ Immunosuppressive therapy
+ Arsenic poisoning
+ Chronic inflammation (burn scars, draining sinus tracts)
Actinic Keratosis
Hyperkeratotic, scaly papule/plaque
Precursor to SCC
Keratoacanthoma
Well-differentiated SCC
Develops rapidly & regresses spontaneously
“Cup-shaped” tumor with keratin debris
Melanocytes
Derived from neural crest
Found in stratum basalis
Synthesize melanin in melanosomes
Transfer melanosomes to keratinocytes
Vitiligo
Autoimmune destruction of melanocytes
Loss of skin pigmentation & tanning
Albinism
Congenital defect in tyrosinase; Impaired melanin production
Ocular or oculocutaneous
Increased risk of skin cancer
Freckle
Small tan-brown macule
Darkens when exposed to sunlight
Due to increased number of melanoSOMES
Freckle
Small tan-brown macule
Darkens when exposed to sunlight
Due to increased number of melanoSOMES
Melasma
Mask-like hyperpigmentation of cheeks
Seen in oral contraceptives & pregnancy
Nevus (Mole)
Benign neoplasm of melanocytes
May be congenital (with hair growing from it)
***Melanoma would NOT have hair
May be acquired
-Along epidermal-dermal junction (Junctional Nevus)
-Extends into dermis (Compound Nevus)
-Loses junction (Intradermal Nevus)
Dysplasia within nevus, precursor to melanoma
Melanoma
Malignant neoplasm of melanocytes
Know the ABCDE’s, Diameters > 6 mm
Risk: Same as BCCs
+ Dysplastic Nevus Syndrome (AD)
