105: Cancer of the Skin Flashcards
T or F: Cutaneous melanoma has no age predilection. It can occur in adults in all ages.
True
T or F: Cutaneous melanoma is predominantly a malignancy of white-skinned people (98%)
True
Sex predilection of cutaneous melanoma
Male
Diagnosis at late fifties
Strongest risk factors for melanoma
- Presence of multiple, benign OR atypical nevi
2. Family or personal history of melanoma
Marker of increased risk of melanoma
Presence of melanocytic nevi, common or dysplastic
Congenital melanocytic nevi and classification accdg to diameter
Small: = 1.5cm
Medium: 1.5-2.0cm
Giant: >20cm
Management for giant melanocytic nevus (bathing trunk nevus)
Prophylactic excision early in life
6% lifetime risk of melanoma
T or F: The higher the number of total body nevi, the higher the risk of melanoma
True
Surveillance for patients diagnosed with melanoma
Lifetime
Should be done by dermatologist and include total body photography and dermoscopy if appropriate
Cell cycle regulatory gene responsible for 20-40% of cases of hereditary melanoma
cyclin-dependent kinase inhibitor 2A (CDKN2A)
Chromosome 9p21
Encodes for tumor suppressor proteins: p16 (cell cycle arrest) and ARF (defective apoptotic response to genotoxic damage)
T or F: Red hair color (RHC) phenotype is associated with increased risk of melanoma.
True
Primary prevention of melanoma and nonmelanoma skin cancer
Protection from the sun
Advise:
Regular use of broadspectrum sunscreens blocking UVA and UVB with SPF atleast 30
Avoidance of tanning beds and midday (10am-2pm) sun exposure
Secondary prevention of melanoma and nonmelanoma skin cancer
- Education
- Screening
- Early detection
Interval of self examination that enhance likelihood of detecting change
6-8 week intervals
ABCDE for early detection of melanoma
Asymmetry Border irregularity Color Variegation Diameter >6mm Evolving (size, shape, color, elevation or new symptoms: bleeding, itching, crusting)
Where do benign nevi usually appear?
Sun-exposed skin above the waist
Rarely: Scalp, Breasts, Buttocks
Average number of benign nevi in adults
10-40 moles
Who should be a candidate for biopsy?
- Any pigmented cutaneous lesion that has changed in size or shape
- Has other features suggestive of malignant melanoma
Margins suggested for excisional biopsy?
1-3mm margins
Definitive treatment for benign nevi
When is incisional biopsy opted rather than excisional biopsy?
If excisional biopsy is not feasible (face, hands, feet)
Through the most nodular or darkest area of lesion
T or F: Cauterization is allowed in biopsy
False. It should be avoided.
Shave biopsies are acceptable
What should we expect in the biopsy reading?
- Breslow thickness
- Mitoses per square millimeter for lesions =1mm
- Presence or absence of ulceration
- Peripheral and deep margin status
Greatest thickness of a primary cutaneous melanoma measured on the slide from the top of the epidermal granular layer, or from the ulcer base, to the bottom of the tumor
Breslow thickness
Four MAJOR types of cutaneous melanoma
Table 105-2
- Lentigo maligna melanoma
- Superficial spreading melanoma
- Nodular melanoma
- Acral lentiginous melanoma
Period at which the skin lesion increase in size but does not penetrate deeply; period most capable of being cured by surgical excision
Radial growth phase
Types: Lentigo maligna melanoma, superficial spreading melanoma, acral lentiginous melanoma
Type of melanoma with no radial growth phase which usually presents as deeply invasive lesion capable of early metastasis
Nodular melanoma
Brown-black to blue-black nodules
Period where tumors begin to penetrate deeply into the skin
Vertical growth phase
The most common variant of melanoma observed in the white population
Superficial spreading melanoma
Most common site for melanoma in men and women
Men: Back
Women: Back and Lower leg (knee to ankle)
Type of melanoma occurring on the palms, soles, nail beds, and mucous membranes
Acral lentiginous melanoma
Most common types of melanoma in blacks and East Asians
- Acral lentiginous melanoma
2. Nodular melanoma
Other SITES where melanoma can arise
- Mucosa of head and neck (nasal cavity, paranasal sinuses, oral cavity)
- GI tract
- CNS
- Female genital tract (vulva, vagina)
- Uveal tract of the eye
Fifth type of melanoma associated with fibrotic response, neural invasion, and greater tendency for local recurrence
Desmoplastic melanoma
Type of melanoma commonly seen on sun-exposed surfaces, particularly malar region of cheek and temple
Lentigo maligna melanoma
Effects of UV solar radiation on skin
- Genetic changes in skin
- Impairs cutaneous immune function
- Increases the production of growth factors
- Induces formation of DNA-damaging reactive oxygen species affecting keratinocytes and melanocytes
Mechanism of BRAF mutation found in most benign nevi
Point mutation (T-->A mucleotide change) Valine-to-glutamate amino acid substitution
Best predictor of metastatic risk
Brelow thickness