From the Guidelines
For melanoma, a narrow excisional/complete biopsy with 1- to 3-mm margins is the preferred method, as it allows for the entire breadth of the lesion to be removed and provides sufficient depth to prevent transection at the base 1. This approach enables complete histological evaluation of the lesion's depth and characteristics, which is crucial for accurate staging and treatment planning.
- The biopsy technique may be accomplished by fusiform/elliptical or punch excision or deep shave/saucerization removal to depth below the anticipated plane of the lesion.
- Partial/incomplete sampling (incisional biopsy) is acceptable in select clinical circumstances, such as facial or acral location, very large lesion, or low clinical suspicion or uncertainty of diagnosis 1.
- In cases of suspicious nail lesions, the nail matrix should be sampled, and for subungual lesions, the nail plate should be removed to expose the underlying lesion, followed by an excisional or incisional biopsy depending on the size of the lesion 1.
- The choice of biopsy method depends on the specific clinical circumstances, but the primary goal is to obtain a complete and accurate diagnosis to guide further management.
- The procedure is typically performed under local anesthesia in an outpatient setting, with minimal discomfort and recovery time.
- After the biopsy, the tissue is examined by a pathologist who evaluates features like tumor thickness, ulceration, mitotic rate, and other characteristics that help determine the melanoma's stage and guide further management 1.
From the Research
Types of Biopsy for Melanoma
- Excisional biopsy: considered the gold standard for diagnosing melanoma, as it allows for the removal of the entire lesion and provides accurate staging information 2, 3, 4
- Shave biopsy: commonly used, but may transect the lesion and result in inaccurate Breslow thickness assessment 2, 5
- Punch biopsy: may be used, but can result in positive peripheral margins and a higher risk of finding residual tumor in the wide local excision (WLE) 2, 5
- Incisional biopsy: not recommended, as it can result in false negatives and is often incomplete 3
Comparison of Biopsy Types
- Excisional biopsy is associated with fewer positive deep margins and less risk of finding residual tumor in the WLE compared to shave and punch biopsies 2, 4
- Shave and punch biopsies may underestimate true T-stage, but there is no difference in need for reoperation due to T-upstaging based on initial biopsy type 5
- Punch biopsy may result in a larger mean WLE area compared to shave and excisional biopsies 2
Recommendations for Biopsy
- Excisional biopsy is recommended as the technique of choice for evaluating lesions suspected of being primary melanomas 2, 3, 4
- Shave and punch biopsies may be used, but should not be discouraged for the diagnosis of melanoma when used appropriately 2, 5
- Incisional biopsy is not recommended due to its limitations and potential for false negatives 3