Epidermoid & pilar cysts (sebaceous cysts)

Question 1

Define sebaceous cysts

Answer 1

Epithelium-lined, keratinous, debris-filled cyst arising from a blocked hair follicle

AKA epidermal cyst

Question 2

Aetiology of sebaceous cysts

3

Answer 2

Occlusion of pilosebaceous gland
Can be caused by traumatic insertion of epidermal elements into dermis
Embryonic remnants

Question 3

Risk factors for sebaceous cysts

Answer 3

Gardner’s syndrome

Question 4

Epidemiology of sebaceous cysts

age/prevalence

Answer 4

VERY COMMON at any age

Question 5

Presenting symptoms of sebaceous cysts

4

Answer 5

Non tender slow growing skin swelling
Often multiple
Common on hair bearing regions of body (e.g. face, scalp, trunk, scrotum)
May become red, hot & tender if there’s superimposed infection/inflammation

Question 6

Signs of sebaceous cysts on physical examination

3

Answer 6

Smooth tethered lump
Overlying skin punctum
May discharge granular creamy material that smells

Question 7

Investigations for sebaceous cysts

2

Answer 7

NONE needed

Skin biopsy of FNA may be used to rule out other differentials

Question 8

Define Gardner’s syndrome

Answer 8

autosomal dominant condition characterised by multiple polyps in colon & extra-colonic sites (e.g. sebaceous cyst, thyroid cancer, fibroma)