Skin Pathology Flashcards
Layers of the epidermis
Come lets get some beers
Corneum Lucidium Granulosum Spinosum Basale
What area is affected in Bullous pemphigoid
Dermo-epidernal junction
Basement membrane- deeper bullae
What area is affected in pemphigus vulgaris
Intraepidermal
More superficial
Clinical features of pemphigoid
Large tense bullae on erythematous base. Often on forearms, groin and axillae. ELDERLY.
Bullae do not rupture as easily as pemphigus
Clinical features of pemphigus
Bullae are easily ruptured. Found on skin AND mucosal membranes
Histology of pemphigoid
Subepidermal bulla with eosinophils
Linear deposition of IgG along basement membrane
Histology of pemphigus
Intraepidermal bulla
Netlike pattern of
intercellular IgG deposits
What area does Pemphigus foliaceus affect
What are the clinical features and the diagnosis
o Top layer is very thin so never blisters
o IgG-mediated – outer layer of stratum corneum shears off
o Diagnose with immunofluorescence
Clinical features of discoid eczema
o Flexor surfaces
o Very itchy; plaques form
Clinical features and pathophysiolofgy of contact dermatitis
o Itchy; latex and nickel
Itchy hyperparakeratosis (thickening)
Epidermis gets thicker lichenification
o
Pathophysiology:
Epidermis gets thicker
Eczema is spongiotic because there is oedema in between the keratinocytes
T cell mediated and eosinophils are recruited
Pathophysiology and clinical features of plaque psoriasis
Extensor surfaces
o Silver plaques (similar to discoid eczema)
o Pathophysiology:
Normal keratinocyte turnover time = 56 days
Psoriasis keratinocyte turnover time = 7 days
Rapid turnover - epidermis thicker
A layer of parakeratosis (nuclei in S. corneum) forms at the top
Stratum granulosum disappears as not enough time to form it; and dilated vessels form
Munro’s microabscesses form, made up from recruitment of neutrophils
Clinical features of Lichen planus
o Papules and plaques of purplish-red colour on the wrists and arms
In mouth it presents as white lines (Wickham striae)
Pathophysiology of Lichen planus
T-lymphocytes have destroyed bottom keratinocytes
Creates band-like inflammation
Cannot see where dermis finished, and epidermis starts
Clinical features of Seborrhoeic Keratosis
Rough plaques, waxy, “stuck on” appear in middle age / the elderly
Harmless and benign
Histopathology of Seborrhoeic keratosis
Lots of growth and ordered proliferation
Ordered and benign growth
“Horn cysts” – epidermis entrapping keratin
Characteristics of basal cell carcinoma
o Rolled, pearly-edge, central ulcer, telangiectasia
“Rodent ulcer” as it burrows away
o Benign but can disfigure
o Occurs in sun-exposed areas
Histopathology of BCC
Dysplastic change
Cancer from keratinocytes at bottom of epidermis
Cannot break through the BM cannot metastasise
Bowen’s Disease Characteristics
Pre-malignant
Intra-epidermal squamous cell carcinoma in situ
Flat, red, scaly patches on sun-exposed areas
Bowen’s disease histology
Full thickness atypia/dysplasia
Basement membrane intact – i.e. not invading the dermis
Squamous Cell carcinoma features
When Bowen’s has spread to involve dermis
Similar clinical features to Bowen’s but may ulcerate
Atypia/dysplasia throughout epidermis,
Nuclear crowding and
spreading through basement membrane into dermis
Histopathology of malignant melanoma
atypicalmelanocytes;initiallygrowhorizontallyinepidermis(radialgrowthphase); then grow vertically into dermis (vertical growth phase); vertical growth produces “buckshot appearance” (=Pagetoid cells)
Most important prognostic factor of MM
Breslow thickness
Clinical features of MM
o Irregular border o Variable pigmentation o Bleeding o Itchy o Growing
