What is the role of biopsy in the management of melanoma, and what are the American Academy of Dermatology clinical practice guidelines on primary cutaneous melanoma?

Updated: Mar 08, 2019
  • Author: Jonathan B Heistein, MD; Chief Editor: Gregory Gary Caputy, MD, PhD, FICS  more...
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Answer

Answer

Perform biopsy on all lesions suggestive of melanoma; sample the thickest part of the lesion. Maintain a low threshold to perform biopsy because the procedure is easy and safe. If the resection will not result in a disfiguring defect, excisional biopsy with a 2-mm skin margin and extension to the subcutaneous tissue is suggested for lesions less than 1.5 cm in diameter. Take care to leave scars in locations where re-excision is not difficult. If the lesion is large or located in an anatomic area where skin removal would cause disfigurement, an incisional biopsy may be performed. A full-thickness core punch biopsy in the most raised or irregular area is suggested, with the understanding that this area may not be the thickest area.

Contraindications

Biopsy of a suggestive lesion has no contraindications. Even with widely metastatic melanoma, local control can be attempted.

American Academy of Dermatology clinical practice guidelines

Guidelines released in November 2018 by the American Academy of Dermatology on the evaluation and management of primary cutaneous melanoma include the following [8] :

  • Evidence strongly indicates that Breslow thickness, ulceration, and dermal mitotic rate are important predictors of patient outcome in primary cutaneous melanoma
  • The recommended first-line treatment for any-thickness primary cutaneous melanoma, as well as for melanoma in situ, is surgical excision with histologically negative margins; tumor thickness should dictate the margins
  • Surgical margins for invasive cutaneous melanoma, as measured clinically around the primary tumor, should be a minimum of 1 cm and a maximum of 2 cm, although narrower margins can be employed to accommodate function and/or anatomic location; it is recommended that the excision be as deep as, but not inclusive of, the fascia
  • It is not recommended that asymptomatic patients with newly diagnosed stage 0-II primary cutaneous melanoma undergo baseline radiologic imaging and laboratory studies
  • For cutaneous melanoma at baseline, radiologic imaging and laboratory studies should be conducted only to assess the specific signs or symptoms of synchronous metastasis (regional nodal or distant)
  • At baseline or when physical examination of lymph nodes is equivocal and requires surveillance, the employment of lymph node ultrasonography is encouraged; surveillance with such imaging is also encouraged in patients who meet criteria for sentinel lymph node biopsy (SLNB) but do not undergo the procedure, in patients in whom SLNB is not possible or is technically unsuccessful (eg, because lymphoscintigraphic dye migration has failed and a draining sentinel lymph node cannot be identified), and in those in whom, despite a positive SLNB, complete lymph node dissection is not performed
  • Regular clinical follow-up represents the most important strategy for detecting cutaneous melanoma recurrence; the need for further radiologic or laboratory studies to detect local, regional, or distant metastatic disease should be determined via history (review of systems) and physical examination
  • Patients should be taught self-examination of the skin and lymph nodes in order to detect recurrent disease or new primary cutaneous melanoma
  • For the first 3 months of BRAF inhibitor monotherapy, patients with numerous squamoproliferative neoplasms should undergo dermatologic evaluation every 2-4 weeks, although less skin toxicity is associated with the standard treatment, combination BRAF/MEK inhibition
  • Patients being treated with immune checkpoint inhibitors should undergo dermatologic evaluation within the first month of therapy, with such assessment being continued as needed to manage dermatologic side effects

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