Squamous cell carcinoma

Question 1

What are the risk factors for SCC?

Answer 1

• Excessive UV exposure
• Pre-malignant conditions (actinic keratoses)
• Chronic inflammation (leg ulcers, wound scars)
• Immunosuppression
• Genetic predisposition
• Exposure to chemical carcinogens

Question 2

What is the appearance of SCC?

Answer 2

Classic presentation is painless, non-healing, bleeding ulcer

• Most commonly affects face and neck
• Initial appearance may be plaque-like, papillomatous, and/or verrucous
• All forms eventually ulcerate
• Ulcers typically have red, everted edges
• Floor of the ulcer resembles granulation tissue and bleeds easily
• Skin around the ulcer is inflamed and indurated

Question 3

Describe the typical growth of a squamous cell carcinoma.

Answer 3

• Locally invasive but grows slowly

Question 4

What is the rate of metastasis in SCC?

Answer 4

~2%

Question 5

What are the 2 main stages of SCC?

Answer 5

1. Carcinoma-in-situ (Bowen disease): atypical keratinocytes are confined to the epidermis
2. Invasive cSCC: atypical keratinocytes cross the basement membrane of the epidermis and invade the dermis

Question 6

What investigations should be done if SCC is suspected?

Answer 6

• Punch biopsy (diagnostic and therapeutic)
• Wedge biopsy (esp for larger lesions such as Marjolin ulcer)
• Excisional biopsy
• Shave biopsy (carcinoma-in-situ)

Staging:

• Imaging (CT/MRI)
• Lymph node biopsies, FNAC

Question 7

What are the main differentials for SCC?

Answer 7

• BCC (BCC will grow more slowly)
• Keratoacanthoma
• Actinic keratosis
• Seborrheic keratosis

Question 8

What is the treatment of SCC?

Answer 8

• Surgical excision
• Cryotherapy or curettage for carcinoma-in-situ
• Radiotherapy
• Chemotherapy