The art and science of surgical margins for the dermatopathologist

Abstract

Basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and primary cutaneous melanoma (PCM) are the major forms of skin cancer. Surgical excision is one of the most frequently utilized treatment modalities for these tumors.

Methods: literature review.

Results: recommendations for lateral surgical excision margin (LEM) for BCCs is 4 mm for low-risk BCCs and Mohs surgery or resection with complete circumferential peripheral and deep margin assessment for high risk. Recommended LEM is 4-6 mm for low-risk SCCs and Mohs surgery or resection with complete circumferential peripheral and deep margin assessment for high risk BCCs. If SCC or BCC is >20 mm in area L with no other high-risk factors and can be repaired primarily, 10-mm clinical margins may be used. Recommended LEM is 5 mm for melanoma-in-situ; 1 cm for PCM <1 mm (Breslow); 1-2 cm for PCM 1.01-2 mm (Breslow); and, 2-3 cm for high-risk PCM >2.01 mm (Breslow). Tumor subtype-specific recommendations for histologic margins are offered which provide the greatest degree of certainty regarding the completeness of excision.

Conclusion: Recommendations can be made regarding appropriate surgical excision margins by classifying skin cancers as low-risk or high-risk based on histopathological and clinical factors. Ascertaining that histopathologic margins are free of tumor is not a perfect science and requires thoughtful sampling, grossing, and staining procedures.