Epidermoid & Pilar Cysts (sebaceous cysts)

Question 1

Definition

Answer 1

Epithelium-lined, keratinous, debris-filled cyst arising from a blocked hair follicle. Also known as an epidermal cyst.

Question 2

Aetiology

Answer 2

· Occlusion of the pilosebaceous gland

· Can be caused by traumatic insertion of epidermal elements into the dermis

· Embryonic remnants

Question 3

Risk factors

Answer 3

o Gardner’s Syndrome = autosomal dominant condition characterised by the presence of multiple polyps in the colon and in extra-colonic sites (e.g. sebaceous cyst, thyroid cancer, fibroma)

Question 4

Epidemiology

Answer 4

VERY COMMON at any age

Question 5

Presenting symptoms

Answer 5

· Non-tender slow-growing skin swelling

· There are often multiple

· Common on hair-bearing regions of the body (e.g. face, scalp, trunk or scrotum)

· May become red, hot and tender if there is superimposed infection or inflammation

Question 6

Signs on physical examination

Answer 6

· Smooth tethered lump

· Overlying skin punctum

· May discharge granular creamy material that smells bad

Question 7

Investigations

Answer 7

· NONE needed

· Skin biopsy or FNA may be used to rule out other differentials

Question 8

Management plan

Answer 8

· Conservative
o May be left alone if its not causing the patient any distress

· Surgical
o Excision of the cyst under local anaesthesia

· Medical
o Antibiotics if there is an infection

Question 9

Possible complications

Answer 9

· Infection

· Abscess formation

· Recurrence (if incomplete excision)

· May ulcerate

Question 10

Prognosis

Answer 10

· EXCELLENT

· Most do NOT require treatment