Evaluation and Treatment Approach for Pigmented Skin Lesions
Suspicious pigmented skin lesions should be evaluated using the ABCDE criteria and completely excised with a 2-5 mm margin for definitive diagnosis and treatment. 1
Clinical Evaluation
Primary Assessment
Use the ABCDE criteria to identify suspicious lesions 1, 2:
- A: Asymmetry
- B: Border irregularity
- C: Color heterogeneity
- D: Diameter (especially >6 mm)
- E: Evolution (recent change) - must co-exist with at least one other criterion
Alternative assessment criteria include the "three change criteria" 1:
- Change in size
- Change in color
- Change in shape
Additional warning signs include 1:
- Diameter >7 mm
- Hypersensitivity
- Bleeding
- Inflammation
Diagnostic Tools
Dermoscopy: Improves diagnostic accuracy when performed by experienced clinicians 1, 3
- Helps differentiate melanocytic from non-melanocytic lesions
- Can identify seborrheic keratosis, pigmented basal cell carcinoma, or hemangioma
- Not recommended as routine technique unless the provider is experienced
Full skin examination: Required for any patient with suspicious lesions 1
- Document site and size of pigmented lesions
- Record other pigmented lesions
- Clinical photographs may be helpful
- Examine for lymphadenopathy and hepatomegaly
Biopsy Approach
Recommended Technique
- Complete excisional biopsy is the standard practice 1, 4:
- Full-thickness skin biopsy
- Include entire lesion with 2-5 mm clinical margin laterally
- Include cuff of subdermal fat
- Use elliptical incision with long axis parallel to skin lines
- Use scalpel rather than laser or electrocautery
Rationale for Complete Excision
- Provides definitive diagnosis
- Allows assessment of all histological parameters, especially thickness
- Enables complete evaluation of margins
- Eliminates need for further treatment if benign
- Prevents misdiagnosis from partial sampling 1
Techniques to Avoid
Shave and punch biopsies are not recommended because they 1, 4:
- Make pathological staging impossible
- May miss deeper components of the lesion
- Can lead to sampling error
Incisional biopsy is only acceptable in specific situations 1:
- Differential diagnosis of lentigo maligna on the face
- Acral melanoma
- Never appropriate in primary care
Histopathological Assessment
Essential Histopathology Report Elements 1
- Melanocytic nature confirmation and malignancy status
- Maximum tumor thickness in millimeters (Breslow method)
- Completeness of excision assessment
- Level of invasion (Clark)
- Presence/extent of regression
- Presence/extent of ulceration
Optional Parameters
- Histological type and variants
- Pre-existing lesion
- Mitotic rate
- Vascular invasion
- Neurotropism
- Cell type
- Tumor lymphocyte infiltration
- Growth phase (vertical or radial)
Special Considerations
High-Risk Individuals
Patients requiring special surveillance 1, 2:
- Previous melanoma history
- Atypical mole syndrome
- Giant congenital pigmented nevi
- Family history of melanoma (≥3 cases)
Management of high-risk individuals 1:
- Regular follow-up
- Education on self-examination
- Photography may aid early detection
- Genetic counseling for those with strong family history
Common Pitfalls to Avoid
Prophylactic excision of small congenital nevi without suspicious features is not recommended 1
Partial biopsies can lead to misdiagnosis due to sampling error 1, 5
Improper excision technique (e.g., transverse rather than longitudinal incision) may necessitate skin grafting during re-excision 1
Failure to recognize atypical presentations of melanoma, which can mimic benign lesions 2
Delayed diagnosis in persons with darker skin, who are often diagnosed at later stages 2
Inadequate monitoring of immunosuppressed individuals who develop more aggressive skin cancers 2
By following this systematic approach to evaluating and treating pigmented skin lesions, clinicians can improve early detection of melanoma while minimizing unnecessary procedures for benign lesions.