Cysts

Question 1

Define

Answer 1

Sebaceous cysts is a misnomer as these cysts are not of sebaceous origin

• Epidermal cysts (also known as epithelial or infundibular cysts)

Intradermal or subcutaneous tumours
Epidermoid cysts may occur anywhere on the body but occur most often on the face, scalp, neck, back and scrotum

• Pilar cysts (also called trichilemmal cysts)

Clinically indistinguishable from epidermal cysts
They contain keratinous material, are usually multiple and there is often an autosomal dominant inheritance

Commonly result due to implantation of epidermis in the of dermis due to trauma/surgery
Can also be caused by a blocked pore or for bacteria

Question 2

Causes

Answer 2

Occlusion of the pilosebaceous gland

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

Embryonic remnants

Risk Factors

• 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 3

Epidemiology

Answer 3

VERY COMMON at any age

Question 4

Symptoms

Answer 4

• 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 5

Signs

Answer 5

Smooth tethered lump

Overlying skin punctum

May discharge granular creamy material that smells bad

Question 6

Investigations

Answer 6

NONE needed

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

Management:

Conservative

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

Surgical

Excision of the cyst under local anaesthesia

Medical

Antibiotics if there is an infection