Plastics

Question 1

Three types of dermal appendage

Answer 1

Hair follicles

Sweat glands

Sebaceous glands

Escape destruction in partial-thickness burns and have a source of new cells for reconstitution of the epidermis

Question 2

Type of sweat gland affected by hidradenitis suppurativa

Answer 2

Apocrine

Hidradenitis suppurativa affects apocrine sweat glands - secrete must liquid into axilla, ears, eyes, nipples, perianal region, genitals

Question 3

Types of sweat gland

Answer 3

Eccrine: secrete salt and water for skin

Apocrine: musty liquid
-Hidradenitis suppurativa

Question 4

Stages of wound healing

Answer 4

Lag phase
- 2-3 days
-inflammatory response

Proliferative phase
- 3 weeks
-Fibroblast migration
-Capillary ingorwth (granulation)
-Collagen synthesis and gain in tensile stremgth -Wound contraction

Plateu phase
- 6 months
-Organisation of scar
-Slow final gain in tensile strength (80% of original)

Question 5

Use of flaps

Answer 5

Flaps are used when the recieving site has a poor blood supply and hence a graft won’t take

e.g. over joints, tendons, bone

Question 6

Eschar

Answer 6

Epidermis and dermis are converted into a coagulum of dead tissue

Question 7

Fluid loss due to oedema

Answer 7

An increase of 2 cm in the diameter of the leg represents the accumulation of over 2 litres of excess
interstitial fluid.

Question 8

IV fluids in burns

Answer 8

Required in burns >15% adults

> 10% Children

Question 9

Parkland formula

Answer 9

4 X weight (kg) X %BSA

1/2 over 8 hours,
1/2 over the next 16 hours

Question 10

Sebaceous cysts

Answer 10

Sebaceous or epidermoid cysts

Dermal swellings covered by epidermis

Thin wall of flattended epidermal cells and contain sebum + epitheial debris

Soft smooth hemispherical swellings over which the skin cannot be moved.

Surface punctum

Infection: cyst becomes hot, red and painful.

Infected cysts are incised to allow the infected material to escape.

Excision is deferred until the inflammation has settled.

Question 11

Dermoid cysts

Answer 11

Arise from nests of epidermal cells that have been sequestered in the dermis during development or implanted from trauma

Lined by squamous epithelium and
contain sebum, degenerate cells and, in some cases, hair.

A soft rubbery swelling forms deep to the skin.

Congenital dermoid cysts found at sites of embryonic fusion: face, base of nose, forehead, occipit
- External angular dermoid most common: lies at junction of maxilla frontal bones on later superior orbit

Question 12

Congenital dermoid cysts

Answer 12

Found at sites of embryonic fusion: face, base of nose, forehead, occipit

External angular dermoid most common: lies at junction of maxilla frontal bones on later superior orbit

Question 13

Senile warts (seborrhoeic kerratosis)

Answer 13

Basal cell papillomas

Common in the elderly

Form yellow-ish brown or black greasy plaque

Cracked surface that falls off in pieces

Tx: Curettage

Question 14

Keratocanthoma

Answer 14

Hemispherical nodule with friabl red centre encrusted with keratin

Often of the face, >50 years of age

Grows rapidly over 6-8 weeks

Heals by shedding its keratin core

Clinically looks like squamous cell carcinoma
–> histologically it can resemble SCC but has a well defined “shoulder”

Question 15

Actinic keratosis

Answer 15

Actinic (solar) keratosis

Pre-malignant keratosis

Small singular/multiple firm warty spots on the face, back, neck hands

Scaly lesions drop off to reveal underlying pre-malignant ulcer

Mx: biopsy to exclude malignancy and then cryotherapy if non-malignant

Question 16

Bowen’s disease

Answer 16

Intra-epidermal skin cancer

Non-invasive, discrete solitary raised brown fissured plaque containing kerratin

Hyperplastic atypical epithelial cells, but there is no
evidence of invasion through the basement membrane

If affects penis or vulvula: erythroplasia of de Queyrat

Question 17

Basal cell carcinoma

Answer 17

Rodent ulcer

Slow growing, locally invasive cancer

Never metastasize

Commonly arise on middle third of face: nose or inner canthus of eye

Hard pearly nodule dimpled in its centre and covered by thin telangiectatic skin

Types:
-Cystic
-Nodular
-Sclerosing
-Morphoeic
-Centrally healing
-Field fire

Question 18

Squamous cell carcinoma

Answer 18

Can affect any area but common on sun-exposed areas

Develops in an area of epithelial hyperplasia or keratosis.

In mucosa: leucoplakia

Hard erythematous nodule, which proliferates to form a
cauliflower-like excrescence or ulcerates to form a malignant ulcer with a raised fixed hard edge.

Grows more quickly than a rodent ulcer but more slowly than a keratoacanthoma

Palpable lymph nodes require regional lymphadenectomy by block dissection

Adjuvant radiotherapy may be required if histology
shows extracapsular spread

Question 19

Lentigo maligna

Answer 19

Hutchinson’s melanocytic freckle

Commonly on face in elderly women

Originate as red-brownish patch the grows slowly, advancing and receeding over years

The edge of the lesion appears serrated

Kaleidoscopic pigmentation of the surface i

Malignancy: brownishred papule that develops eccentrically within the freckle

Question 20

Superifcial spreading melanoma

Answer 20

Most common melanoma

Trunk and exposed parts, middle age

Pre-invasive phase: 1 or 2 years, malignant cells spread
outwards (horizontal growth phase) in the epidermis

Pigmentation is patchy and there may be a wide range
of colours

Invasion of the dermis (vertical growth phase) occurs while the lesion is still relatively small and produces
an indurated nodule, which soon ulcerates or bleeds.

Question 21

Nodular melanoma

Answer 21

Elevated, deeply pigmented melanoma

Any site

Any age

Vertical invasion from the start, no horizontal spreading stage (hence no surrounding pigmented macule)

Nodule enlarges steadily, both centrifugally
and on the surface

Lesion darkens progressively, jet black and glossy

Bleeding
Crusting
Itching, irritation and ulceration

Satellite nodules may form around neglected lesions.

Question 22

Breslow depth

Answer 22

1cm of clearance for every 1mm depth
up to 3cm

Tumour and surrounding skin are excised down to the deep fascia

Question 23

Staging of malignant melanoma

Answer 23

Three stages

I Primary lesion only
Breslow depth

II Primary lesion + regional lymph node or satellite deposit

III Metastatic disease