Skin Cancer Flashcards
What two distinct pathways converge to cause skin cancer?
Direct action of UV on target cells (kertatinocytes) for neoplastic transformation via DNA damage (e.g. p53 mutation)
Effects of UV on the host’s immune system
What are the three main skin cancer types?
Basal cell carcinoma
Squamous cell carcinoma
Malignant melanoma
From most superficial to the most deep, list the three skin cancer types.
Squamous cell carcinoma
Basal cell carcinoma
Malignant melanoma
What is the most common type of skin cancer?
Basal cell carcinoma
Describe the pathophysiology of basal-cell carcinoma.
Basal cells control the process of creating new skin cells
A mutation in the DNA of basal cells causes a basal cell to mutliply and grow rapidly when it would normally die.
Eventually the accumulating abnormal cells may form a tumour.
Is there a genetic risk for basal cells carcinoma?
PTCH gene mutation may predispose a person to this
Were are basal cell carcinomas most commonly found?
80% are found on the head and neck
- UV exposed sites
How common is basal cell carcinoma?
30% of Caucasians will develop a basal cell carcinoma
List the basal cell carcinoma subtypes.
Nodular - most common
Superficial
Pigmented
Morphoeic/sclerotic
Describe the appearance of a nodular basal cell carcinoma.
Nodule (greater tha 0.5cm raised lesion)
Shiny - reflects light
Telangectasia - fine, broken blood vessels
Often central ulceration - the top layer of the dermis has come away
- more likely to bleed
Smooth edges
Describe the appearance of a superficial basal cell carcinoma.
Doesn't have a nodular texture - smoother Telangectasia on microscopy Shiny Small amount of ulceration Quite dry
Describe the appearance of a pigmented basal cell carcinoma.
Ulceration Telangectasia On a sun exposed site Well demarcated, lumpy egde Shiny
What is the differential diagnosis of a pigmented basal cell carcinoma?
Pigmented lesion
Mole
Melanoma
- need to check with a biopsy
Describe the appearance of a morphoeic/sclerotic basal cell carcinoma.
Very similar to normal skin Shiny on flash Well demarcated Telangectasia Central area of depression Slightly raised edge
List the available treatments for basal cell carcinomas.
Surgical excision - gold standard - 3-4mm margin to account for infiltration Curettage and cautery Cryotherapy Photodynamic therapy Topical imiquimod/5-fluorouracil cream Mohs micrographic surgery
Describe curettage and cautery in skin cancer treatment.
Circular scalp instrument is used to scoop away the malignant skin. Cautery is used to burn away any remaining malignant cells
- less accurate as you have to guess the penetration of the cancer
- used in more elderly patients
What is cryotherapy in skin cancer treatment?
Lquid nitrogen is sprayed onto the affected area, and the cancer is frozen off
- no margin control
- sore and causes blistering