Diagnosis of Cutaneous Melanoma

The choice of biopsy technique:
- Varies according to the anatomical site as well as the size and shape of the lesion
Particular attention should be placed on the impact of the biopsy on definitive surgical treatment
Either an excisional biopsy or an incisional biopsy using a scalpel or punch is acceptable
Entire removal of the lesion is generally preferred to allow for accurate pathologic evaluation
Punch biopsies:
- Can be performed for most lesions:
  - Generally, they can be performed when lesions are located on areas where maximum preservation of surrounding skin is important, or
  - Can be completely excised with a punch
- Punch biopsies:
  - Should be performed at the most raised or darkest area of the lesion to sample the most aggressive area of the potential melanoma
Full-thickness biopsy:
- Into the subcutaneous tissue should be performed to ensure accurate staging of the lesion
An excisional biopsy:
- Allows the pathologist to accurately determine the thickness of the lesion, since the entire lesion is available for evaluation
Excisional biopsies:
- Should be performed when the lesion is too large for a punch but still can be removed without excessive surgical intervention
For excisional biopsies:
- A narrow margin of normal-appearing skin (1 to 3 mm) is taken with the specimen
An elliptical incision:
- Is often used to facilitate closure
The biopsy incision should be oriented to facilitate later wide excision (e.g., axially on extremities) and minimize the need for a skin graft to provide wound closure at the time of wide excision
Shave biopsy:
- Is generally discouraged if a diagnosis of melanoma is being considered since incomplete assessment of tumor thickness may result if the deep margin is not cleared
- If a shave biopsy is performed:
  - A deep shave is preferable
In general, I submit all pigmented lesions for permanent section examination and perform definitive surgery at a later time
I generally prefer image-guided fine-needle aspiration biopsy as an initial diagnostic maneuver to document nodal or other melanoma metastases:
- But not to diagnose primary melanomas