Vignettes
Resources
Clinical Features
Superficial spreading melanoma (60-70%)
- Age: 40-60
- 50% in pre-existing nevi
- Male: Trunk; Female: Legs
- Slow horizontal (radial) growth phase → then rapid vertical growth phase: papule or nodule
Nodular (15-30%)
- Age: 50s; Male > Female
- Trunk > Head and neck > Other sites
- De novo vertical growth phase (no radial growth)
- Fast-growing → deep invasion → poor prognosis
Lentigo maligna melanoma (LMM) (10%)
- Age: 60s
- Precursor = lentigo maligna, 5% progress to LMM
- Chronic sun-damaged skin: Face especially nose and cheeks
- Slowly evolving
Acral lentiginous (5%)
- Age: 60s
- Incidence similar in all ethnicities, but over-represented in Asian (45%), African American (70%)
- Palms, soles, nails
- Nail: longitudinal melanonychia, ABCDEF rule
Amelanotic (<2%)
- Can be any of primary types
Desmoplastic (<4%)
- Locally aggressive; LN metastasis uncommon
- Recurrence frequent
- Frequent association with LMM
Spitzoid
Malignant blue nevus
- Head especially scalp. High recurrence + metastasis. GNA11 or GNAQ mutation in 65—75%.
Ocular (5%)
- Conjunctival
- Uveal (GNA11 or GNAQ mutations in 85%): iris, choroid, ciliary body
Mucosal (1%)
- cKIT mutations
- 35% amelanotic → diagnosis at late stage
Clear cell sarcoma
- Melanoma of soft parts (tendon, aponeurosis)
- Distal extremities of teenagers and young adults
- High risk of local and distant metastases
Pregnancy
- No increase melanoma incidence / worsening
- No change in nevi unless physically stretched skin
Childhood
- 2% of all melanoma in <20yo, 0.3% <14yo
- Xeroderma pigmentosum and giant congenital melanocytic nevi are rare → little contribution to childhood melanoma
- ABCD in pediatric:
- A – amelanotic;
- B – bleeding, bump;
- C – color uniformity;
- D – de novo, any diameter
