Cryotherapy, Moh's surgery

Question 1

Define cryotherapy.

Answer 1

Cryotherapy, also known as cryosurgery, uses extremely cold temperatures to treat benign and malignant skin lesions.

It is a widely available, inexpensive, cost-effective, and rapid treatment that rarely requires anesthesia.

Question 2

What are the indications for cryotherapy?

Answer 2

Benign, premalignant and some malignant conditions:

• Benign lesions e.g. solar lentigines, common warts, myxoid cysts, keloids, infections, hidradenitis suppurativa
• Premalignant e.g. actinic keratoses
• Malignant e.g. cutaneous SCC in situ (Bowen’s), intraepithelial neoplasia, BCC, SCC

Question 3

What temperatures must be reached for cryotherapy?

Answer 3

• Melanocytes -5 degrees C
• Benign lesions -25 to -50 degrees C
• Malignant lesions at least -50 degrees C

Question 4

What are the complications of cryotherapy?

Answer 4

• Hypopigmentation of the treated area - melanocytes are very sensitive to low temperatures. Avoid in lip areas on the vermilion border.
• Scarring/retraction

NB: blistering and crusting is expected and is usually followed by healing in 1-3 weeks.

Question 5

Define Mohs surgery.

Answer 5

Mohs micrographic surgery (MMS) is a specialized surgical technique for removing locally invasive, high-risk skin cancers.

MMS provides high cure rates with maximal preservation of unaffected tissue

Question 6

How is Mohs carried out?

Answer 6

1. Local anaesthesia
2. Specimens are cut in horizontal/oblique sections that allow evaluation of the entire peripheral and deep margins of the tumour
3. These are processed into frozen sections
4. Frozen specimens are examined under microscopy
5. Immunostaining may be used for evaluation

Question 7

What are the indications for Mohs surgery?

Answer 7

Locally aggressive tumours at high risk of recurrence or poor borders.

• BCC >5mm in high risk areas like central nose, face, lips, eyelids, periorobital skin, feet, hands
• SCC >19mm, on the face
• Dermatofibrosarcoma protuberans
• Microcystic adnexam carcinoma - rare tumour of the sweat glands
• Extramammary Paget disease - genitalia or axilla
• Melanoma - although this is controversial
• Lentigo maligna

Question 8

What are the complications of Mohs surgery?

Answer 8

Generally low risk of complications

• Bleeding +/- haematoma
• Infection of the wound site
• Flap or graft necrosis following repair
• Dehiscence