Clinical Skin Flashcards
1
Q
Parakeratosis
A
- pathological
- Thickened keratin layer
- Keratins contains spindly nuclear remnants
- usually associated with loss or severe thinning of underlying granular layer
- may be associated with epidermal dysplasia
2
Q
Hyperkeratosis
A
- (non-pathological)
- present in elbow & soles
- thickened keratin layer
- no histological abnormality in keratin layer
- usually associated with thickening of underlying granular layer - hypergranulosis
- seen in cases of chronic trauma like scratching
3
Q
Pemphigus vulgaris
A
- blistering disorder
- auto-AB that result in dissolution of intercell attachments (desmosomes) w/in epidermis & mucosal epithelium
- Clinical presentation:
- superficial blisters & bullae that rupture easily
- ulcerated blisters in oral mucosa are also common
- Light microscope shows:
- tombstone blister
- Acantholysis: disruption of intercell adhesions in cells immediately above basal layer in stratum spinosum
- suprabasal blister
- acantholytic cells: rounded & lose symmetry
- fish-net patter of Ig deposition along plasma membrane of epidermal keratinocytes
4
Q
Bullous pemphigoid
A
- chronic autoimmune disorder
- bullous pemphigoid antigens 1 & 2 present as nl constituents of hemidesmosomes -> auto-ab bind to antigens & stimulate complement deposition & leucocyte infiltration -> degrading eosinophils release proteases that degrade hemidesmosomes
- Rx: topical Corticosteroid
5
Q
Acne vulgaris
A
- occurs almost universally in middle to late teenage years
- hormonal variations & alterations in hair follicles, particularly in sebaceous glands
- Open Comedone (black head): small follicular papules with central keratin plug
- Severe acne: papules, nodules, cysts
- Light microscope:
- development of keratin plug blocking outflow of sebum
- hypertrophy of sebaceous gland
- infection with cane causing bacteria Propionobacter acnes
- inflammation of follicle
- Rx: Vitamin A
6
Q
Vitiligo
A
- depigmentation disorder
- auto-immune
- destruction of melanocytes
- Types: focal, segmental, generalized
- Rx:
- Medical: topical steroid therapy, psolaren photochemotherapy (increases pigmentation), depigmentation
- surgical: autologous skin graft, micropigmentation, melanocyte transplants
7
Q
Psoriasis
A
- due to increased rate of proliferation of mitotic cells, thereby leading thickened epidermis
- leads to shedding of epidermis constantly, resulting in scales seen as whitish patches, especially in extensor aspects of limbs, trunk & lumbosacral region
- autoimmune T-cells (cytokines & cell-mediated autoimmunity)
- increased epidermal turnover (3-5 d); marked epidermal thickening and increase in size of epidermal ridges
- abnormal keratinocyte differentiation: loss of S. granulosum
- parakeratosis: S. corneum thickening & nuclei retention
- weak junctional complexes in superficial layer (silvery scales)
8
Q
Basal Cell Carcinoma
A
- most common invasive cancer in humans
- arises from basal cells of epidermis or epidermal appendages
- tendency to occur in sun-exposed areas and in lightly pigmented people
- pearly papules
- contain prominent, dilated sub-epidermal blood vessels
- rolled out margins
- advanced lesions may ulcerate with extensive local invasion (rodent ulcers)
- nest of uniformly atypical basaloid cells within the dermis (basophilic)
- separated from adjacent stroma by thin clefts
- basophilic cells with dark staining nuclei and sparse cytoplasm
- cells at the periphery tend to be arranged radially with their long axes in parallel arrangement (pallisade arrangement
9
Q
Squamous Cell Carcinoma
A
- 2nd most common tumour arising in sun exposed sites
- higher incidence in men than women
- DNA damage induced by exposure to UV light
- p53 mutations
- commonly associated with chronic immunosuppression: chemotherapy or organ transplant
- increased susceptibility of keratinocytes to infection and transformation by oncogenic viruses
- other risk factors
- industrial carcinogens like tars & oils
- chronic ulcers
- light microscopy shows:
- nodular & ulcerated lesions
- well differentiated
- highly keratising
- larger than nl cells
- nuclear pleomorphism: keratin pearls
- nodular & ulcerated lesions
10
Q
Malignant Melanoma
A
- malignant transformation of melanocytes
- most common on sun exposed surfaces
- lightly pigmented individuals are at higher risk
- important pre-disposing factors:
- inherited genes: mutations in RB tumour supressor gene
- sun exposure
- clinical features:
- usually asymptomatic so frequently undetected; very dangerous
- itching or pain may occur
- changes in colour, size or shape of a pigmented lesion most important clinical indicator
- A: assymetry
- B: borders (irregular)
- C: colour (variegated)
- D: diameters (>6mm)
- E: elevated lesion
- Light microscopy shows:
- ayptical melanocytes in epidermis & dermis with large nuclei & prominent nucleoli
- radial growth: horizontal spread of melanoma within epidermis
- vertical growth: tumour cells invade deeper layers
- metastases may occur: usually fatal
11
Q
Neurofibromatosis (Von Reclinghausens Disease)
A
- not a skin lesion
- nerve-ending lesions