Histo path - Skin Flashcards
Itchy Rash
Inflammatory infiltrate
Dilated dermal capillaries
Spongiosis (intracellular)
Acute eczema
Think inflam = dilated cap = fluid
Itchy Rash
Acanthosis (epidermal hyperplasia due to ↑ in stratum spinosum)
Crusting/Scaling
Chronic Eczema
Think thickening of skin = lichenification.
Think grey, leathery, crusty
Itchy Rash
Child, atopy, face scalp
Flexures if older
Atopic Dermatitis
Erythema, swelling, itchy rash
on wrist, ear lobes, neck
Contact Dermatitis
Think urticaria, think watch, ear rings and necklace. Commonly to metal and rubber.
Child, yellow scale on scalp, non itchy
Seborrheic Dermatitis
Remember it is not itchy or mildly itchy. Will be in sebaceous areas
red plaque, Silver scale, when scraped left pin point bleeding. On extensor surfaces.
Microabscesses in epidermis, neutrophil infiltration (not eosinophilic)
plaques formed at injury site
pitting, thickening, irregular contour nails
Psoriasis
pin point bleeding is called Auspitz’ sign
plaques forming at injury site is called Koebner phenomenon
Scaly rash
Histo: Nuclei in Stratum Corneum Loss of granular layer Rete ridges have test tube appearance Neutrophil infiltration in s. corneum
Psoriasis
Nuclei in s. corneum is called parakeratosis. This process happens in high turn over cells and is a way of keratinising cells. Inflammation or neoplasm.
With parakeratosis, granular layer is lost
Neutrophil infiltration in S. corneum aka Munro’s Microabscesses happens only in psoriasis
Red itchy rash with silver scale in ‘body folds’ - groin and sub mammary areas. 30 years old.
Flexure psoriasis
Raindrop plaques in child, 2 weeks after throat infection
Guttate psoriasis
Itchy, purple, polygonal, plaque, pimple with fine white network, lymphocytic infiltrate
Inner wrists or inside mouth
Histo: Saw tooth rete ridges
Lichen Planus
White network is called Wickam’s Striae
Thought to be an autoimmune disorder, assoc with Hep C
Scattered, red and round plaque-like in appearance
Affects flexural surfaces Increased fluid between keratinocytes in the epidermis, stretching them apart. Generally see eosinophils in the inflammatory infiltrate. (not neutrophilic)
Discoid Eczema
Pt has coeliac - itchy vesicle on elbows and buttocks.
Histo shows IgA bound to basement membrane
Microabscesses which coalesce to form subepidermal bullae. Neutrophil & IgA deposits at tips of dermal papillae
Dermatitis herpetiformis
Subepidermal, BM membrane
Elderly man with large tense blistering of skin on erythmateous base.
Subepidermal bulla with eosinophils and linear deposition of IgG along basement membrane
Bullous Pemphigoid
IgG binds to hemidesmosome of BM (type 2 hy)
Often on forearms, groin and axillae.
PemphigoiD - Deep
Nikolski sign negative
Fragile small blisters on skin and mucosal surfaces
Intraepidermal bulla
Netlike pattern of intercellular IgG deposits
Acantholysis
Pemphigus vulgaris
IgG binds to desmosomal proteins
PemphiguS - superficial
Nikolski sign positve - rubbing causes exfoliation
Desmoglein antibodies
Pemphigus follaceous
Elderly lady with sharply demarcated pigmented lesion that protrudes above surface of skin
Appears to be stuck to skin
Is soft, tan-black, “greasy” surface
Thick epidermis
Seborrhoeic Keratosis
Leser-Trélat sign:
Sudden appearance or increase in number and size of seborrheic keratoses, associated with internal malignancy A paraneoplastic phenomenon typically associated with GI malignancy
Man who is well tanned has Tan-brown, red or skin colored, circumscribed scaly lesions with sandpaper texture
Solar elastosis Parakeratosis Atypia/dysplasia Inflammation Not full thickness
Actinic keratosis
Male, sun exposed, on face
Flesh colored, dome shaped lesion with central, keratin-filled crater
Grew for 3 weeks then subsided
Keratoacanthoma
Flat/Slightly raised, large scaly erythematous plaque with irregular border on skin exposed to sunlight OR on the trunk
Atypia throughout the epidermis
Includes nuclear hyperchromasia and multinucleation, individual cell dyskeratosis, increased mitotic figures, atypical mitotic figures
Does not invade through the basement membrane
Bowen’s Disease
Flat/Slightly raised, large scaly erythematous plaque with irregular border on skin exposed to sunlight OR on the trunk
Atypia throughout the epidermis
Includes nuclear hyperchromasia and multinucleation, individual cell dyskeratosis, increased mitotic figures, atypical mitotic figures
Very invasive through the dermis
Squamous Cell Carcinoma
2nd most common
Slow growing, telangectasic ulcerated nodule on a 65 year old man’s nose. Has a pearly look with a rolled edge.
Cells with scant cytoplasm and elongated hyperchromatic nuclei and peripheral palisading of surrounding stroma
Basal Cell Carcinoma
‘baslow blue’? often don’t spread but will be ugly
A mole that has changed. Irregular colour, borders, itchy and bleeding
Upward migration of melanocytes through epidermis (pagetoid spread)
Size of melanocytes at the top are the same as the bottom
Hyperpigmented and with mitotic figures
Melanoma
ABCDE:
Asymmetrical
Borders irregular
Colour multipigmented
Diameter >5mm
Evolving (growing)
Malignant melanoma measures 2.3cm in thickness. What is it’s breslow thickness
T2
Breslow thickness is the main measure
>2mm thickness epithelial cancer is called T2
<2mm called T1 Best prognostic indicator
Melanoma - elderly person, flat slowly growing black lesion
Lentigo maligna melanoma
Melanoma - Irregular borders with variation in colour
Superficial spreading maligna melanoma
Think ‘superficial’ and ‘variation’
Melanoma - Younger
Nodular maligna melanoma
Melanoma - palms, soles and subungual
areas
Acral Lentiginous melanoma
‘Acro’ and ‘Hands’
Sheets of skin detachment - 8% body surface area
SJS or TEN?
SJS
<10% body surface area in SJS and > 30% in TEN
Nikolsky sign positive
Salmon pink rash appears first (=herald patch) followed by oval macules in Christmas
tree distribution.
Appears after viral illness.
Remits spontaneously
Pityriasis Rosea
