Dermatology
Melanoma
흑색종
Most lethal skin cancer arising from melanocytes
- How common
- Uncommon but rising
- Typical age
- Ages 40+
What is it?
Mutations (e.g., BRAF V600E) drive malignant transformation of melanocytes with metastatic potential.
Commonly affected: Back (men), legs (women), head/neck
How it develops
- UV damageUVB causes DNA mutations
- Melanocyte mutationBRAF, NRAS, p16 mutations accumulate
- Radial growthHorizontal spread within epidermis
- Vertical growth/metsDermal invasion → lymphatic/hematogenous spread
Symptoms
- AsymmetryMole halves differ
- Irregular borderIrregular notched edge
- Color variationMultiple colors within lesion
- EvolvingChange in size/color/symptoms
- Diameter >6 mmLarger than pencil eraser
How it is examined
- ABCDE assessmentAsymmetry, Border, Color, Diameter, Evolving
- DermoscopyAtypical pigment network, blue-gray veil
- Lymph node examCheck regional lymphadenopathy
Imaging
PET-CT for staging once diagnosed.
- Hypermetabolic nodes
- Distant metastases
Brain MRI for stage III/IV; body MRI as needed.
- Brain metastases
- Visceral metastases
Non-surgical care
- Wide local excision1–2 cm margins by Breslow thickness
- Sentinel node biopsyFor Breslow ≥0.8 mm
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Locally advanced or metastatic
Procedures that may be discussed
- Immunotherapy (PD-1: pembrolizumab)
- BRAF/MEK targeted (dabrafenib+trametinib)
- Lymphadenectomy
Outlook
Early stage 99% 5-yr survival; metastatic ~30%.