Dermatology - Terminology

Question 1

Discuss the difference between an incisional and excisional skin biopsy

Answer 1

Incisional: biopsy that takes portion of epidermis, dermis and subcutaneous fat. Used for diagnostic purposes
Excisional: biopsy that takes entire lesion including the epidermis, dermis and subcutaneous fat with a 1-2mm margin. Is diagnostic and therapeutic.

Question 2

Discuss the indications for a shave biopsy, punch biopsy and elliptical incisional biopsy

Answer 2

Shave biopsy: shave off fragment of skin for epidermal lesions with no further extension
- warts
- papilloma
- superficial BCC or SCC
- actinic keratoses
Punch biopsy: core of 1-4mm tissue of the epidermis, dermis and subcutaneous fat for lesions requiring only dermal or subcutaneous tissue for diagnosis
-  inflammatory lesions
- bullous lesions
- dysplastic nevi too large for excision
- nodule
- scalp or hair biopsy
Elliptical excisional biopsy: similar to punch biopsy excepts takes 1-3mm margin of normal tissue. 
- best biopsy method for melanoma

Question 3

List the common topical dermatological medications, their mechanism of action, and some adverse effects

Answer 3

Topical steroids:
- have anti-inflammatory, immunosuppressive, vasoconstrictive and anti-proliferation effects
- skin and subcutaneous tissue atrophy, increased risk of skin infection, peri-oral dermatitis, contact dermatitis, hypopigmentation, ecchymosis, telengectasia purpura, tachyphylaxis, suppressed hypothalamic-pituitary-adrenal axis, ocular hypertension and glaucoma
Vitamin D:
- unknown
- burning and itching skin
Immune modulator (imiquimod):
- activate TLR-7 leading to immune activation
- erythema, ulceration, edema
Anti-parasitic
- neurotoxin to parasites
- drug hypersensitivity, burning and pruritis
Tacrolimus:
- macrolide calcineurin inhibitor which inhibits T cells
- burning

Question 4

Define the following terms:
Macule -
Patch - 
Papule - 
Plaque -
Nodule -
Tumour -
Vesicle - 
Bulla -
Cyst -
Pustule -
Erosion -
Ulcer - 
Indurated - 
Scar - 
Wheal - 
Crust -
Scale -
Lichenification -
Fissure -

Answer 4

Macule - flat lesion <1cm
Patch - flat lesion >=1cm
Papule - raised lesion <1cm
Plaque - raised lesion >=1cm
Nodule - deep, palpable lesion <1cm
Tumour - deep, palpable lesion >=1cm
Vesicle - fluid filled lesion <1cm
Bulla - fluid filled lesion >=1cm
Cyst - epithelial lined collection containing semi-solid or fluid material
Pustule - elevated lesion containing purulent fluid
Erosion - disruption of the skin involving the epidermis alone (will not scar)
Ulcer - disruption of the skin that extends into the dermis or deeper (will scar)
Indurated - lesion that is hard or firm
Scar - replacement fibrosis of dermis and subcutaneous tissue
Wheal - papule or plaque that is transient and blanchable (formed by edema in dermis)
Crust - dried fluid originating from the lesion
Scale - excess keratin
Lichenification - thickening of skin and accentuation of normal skin markings
Fissure - linear slit-like cleavage into the skin