Histopath - Skin Pathology Flashcards
What are the 3 broad layers of skin?
Epidermis
Dermis
Subdermis
What are the 5 layers of the epidermis?
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
(Corn Lovers Grow Some Bales lol)
What are the main cells of the epidermis?
Keratinocytes
How do the keratinocytes move through the epidermis?
From the stratum basale, upwards to the corneum where they shed off and are renewed every 15-30 days
What can be found in the dermis?
Collagen
Elastin fibres
Eccrine swear glands
Sebaceous glands
Hair follicles
+ highly vascular
Function of subcutaneous tissue
Fatty tissue acts as shock absorber
What is hyperkeratosis?
Increase in S. corneum / increased keratin
What is parakeratosis?
Thickening of skin due to scratching as a result of abnormal retention of nuclei in the stratum corneum
What is acanthosis?
Increase in stratum spinosum layer
What is acantholysis?
Decreased cohesions between keratinocytes
What is spongiosis?
Intercellular oedema between keratinocytes
What is lentiginous?
Linear pattern of melanocyte proliferation within stratum basale
What would you see in vesiculobullous lesions?
Bullae
What would you see in spongiotic lesions?
Oedema
What would you see in psoriaform lesions?
Thickened skin
What would you see in lichenoid lesions?
Sheeny plaque
What is the presentation of eczema/dermatitis?
Inflamed, dry itchy rashes
Acute histology of eczema/dermatitis
Spongiosis, inflammatory infiltrate in dermis, dilated dermal capillaries
Chronic histology of eczema/dermatitis
Acanthosis, hyperparakeratosis, crusting, scaling
What is presentation of psoriasis?
Well demarcated pink scaly plaques
Histology of psoriasis
Parakeratosis, loss of stratum granulosum
4 types of bullous diseases
- Dermatitis herpetiformis
- Bullous pemphigoid
- Pemphigus vulgaris
- Pemphigus foeliaceus
What is dermatitis herpetiformis associated with?
Coeliac
Pathophysiology of dermatitis herpetiformis
IgA Abs bind to basement membrane -> subepidermal bulla
Clinical features of dermatitis herpetiformis
Itchy vesicles on extensor surfaces of elbows, buttocks
Histology of dermatitis herpetiformis
Microabscesses
Subepidermal bullae
Neutrophil & IgA deposits
Pathophysiology of Bullous pemphigoid
IgG Abs bind to hemidesmosomes of basement membrane -> subepidermal bulla
Clinical features of Bullous pemphigoid
Large tense bullae on erythematous base
Histology of Bullous pemphigoid
Subepidermal bulla with eosinophils
Linear deposition of IgG along basement membrane
Pathophysiology of Pemphigus vulgaris
IgG Abs bind to demosome proteins 1,3 -> intraepidermal bulla
Clinical features of Pemphigus vulgaris
Easily ruptured (red, raw) flaccid blisters
Histology of Pemphigus vulgaris
Intraepidermal bulla
Netlike pattern of intercellular IgG deposits
Pathophysiology of Pemphigus foliaceus
IgG Ab against desmoglein 1 attacks outer layer of keratinocytes on stratum corneum
Clinical features of Pemphigus foliaceus
V rare
No intact bullae
Appears excoriated
Histology of Pemphigus foliaceus
3 levels of split
3 types of skin cancers
- Squamous cell carcinoma
- Basal cell carcinoma
- Melanoma
Most common kind of skin cancer
BCC
What is the pre-malignant stage of SCC called?
Bowen’s disease
When does SCC become malignant?
Once it has invaded basement membrane
Clinical feature of SCC
Ulcerates
Clinical feature of BCC
Pearly-rolled edge, often with telangiectasia
What are benign melanocytic lesions called?
Naevi/moles
Histology of malignat melanoma
Atypical melanocytes - initially growing horizontally in epidermis (radial growth phase), then vertical growth into dermis
What is the staging system used for prognosis of malignant melanomas?
Breslow thickness
