Management of Pigmented Lesions Suspected of Melanoma Based on Dermatoscopy
The preferred management for pigmented lesions suspected of being melanoma based on dermatoscopy is a narrow excisional biopsy with 1-3 mm margins that encompasses the entire breadth of the lesion and is of sufficient depth to prevent transection at the base. 1
Diagnostic Approach
Initial Assessment with Dermatoscopy
- Dermatoscopy improves diagnostic accuracy when performed by an experienced examiner 1
- Key dermatoscopic features suggesting melanoma include:
Biopsy Techniques
Preferred Technique: Complete Excisional Biopsy
- Complete excisional biopsy with 1-3 mm narrow margins 1
- Should encompass the entire breadth of lesion
- Sufficient depth to prevent transection at the base
- May be accomplished by:
- Fusiform/elliptical excision
- Punch excision
- Deep shave/saucerization removal to depth below the anticipated plane of the lesion 1
Acceptable Alternatives (in specific situations only)
- Partial/incomplete sampling (incisional biopsy) is acceptable only in:
- Facial or acral locations
- Very large lesions
- Low clinical suspicion
- Uncertainty of diagnosis 1
- For suspicious nail lesions, the nail matrix should be sampled 1
- For melanoma in situ, lentigo maligna type, a broad shave biopsy may help optimize diagnostic sampling 1
Special Anatomic Considerations
- Excisional biopsy may be inappropriate for:
- Face
- Palmar surface of hand
- Sole of foot
- Ear
- Distal digit
- Subungual lesions 1
Pathology Reporting
Essential Elements
- Size of specimen
- Tumor thickness (Breslow), measured to nearest 0.1 mm
- Presence/absence of ulceration
- Dermal mitotic rate (using "hotspot" method; number of mitoses/mm²)
- Peripheral and deep margin status
- Presence/absence of microsatellitosis 1
Additional Important Elements
- Histologic subtype
- Presence/absence of regression
- Presence/absence of angiolymphatic invasion
- Presence/absence of neurotropism/perineural invasion 1
Post-Biopsy Management
Surgical Management Based on Breslow Thickness
- In situ melanoma: 0.5 cm margins 1
- <1 mm: 1 cm margins 1
- 1.01-2 mm: 1-2 cm margins 1
- 2.01-4 mm: 2 cm margins 1
4 mm: 2-3 cm margins 1
Sentinel Lymph Node Biopsy Considerations
- Should be considered for melanomas >1 mm in thickness 3
- May be considered for melanomas 0.8-1.0 mm with ulceration 1
- Should be performed by skilled teams in experienced centers 1
Common Pitfalls and How to Avoid Them
Biopsy Technique Pitfalls
- Avoid shave biopsies for suspicious pigmented lesions as they may underestimate depth 3
- Avoid transecting the base of the lesion, which can compromise accurate staging
- Avoid electrocautery for primary excision as it destroys tissue architecture 3
Diagnostic Pitfalls
- Relying solely on clinical examination without dermatoscopy may miss early melanomas 4
- Dermatoscopy performed by inexperienced examiners may lead to misdiagnosis 5
- In vivo dermatoscopy by fully trained dermatologists has better sensitivity than dermatoscopy performed on images 4
Follow-up Recommendations
- For patients with in situ melanomas: no follow-up required 1
- For patients with stage IA melanoma: 2-4 visits over 12 months, then discharge 1
- For patients with stage IB-IIIA melanoma: 3-monthly for 3 years, then 6-monthly to 5 years 1
- For higher-risk patients: more frequent monitoring with complete skin examinations
By following this structured approach to the management of pigmented lesions suspected of being melanoma based on dermatoscopy, clinicians can ensure accurate diagnosis, appropriate staging, and optimal treatment planning to improve patient outcomes.