Excision versus incision biopsy in the management of malignant melanoma

Abstract

Introduction: The incidence of melanoma has increased over the last decade. The Breslow thickness is one of the most important histological parameters. The gold standard for histological diagnosis is an excision biopsy. Incisional, punch or shave biopsies are not recommended as they are often incomplete and can result in false negatives. Objective: To assess the validity of incision versus excision biopsies in the prediction of Breslow thickness in the histopathological analysis of malignant melanoma. Methods: A retrospective review of histopathological records was conducted for all patients undergoing incision biopsy for malignant melanoma. The Breslow thicknesses of the incisional biopsies were matched to the later corresponding excisional biopsies. The demographical data, site of melanoma and histological subtype were also examined. Results: Sixty patients between 1st January 2005 and 31st December 2013 were identified. The most common area biopsied was the upper and lower limbs – 50%. The Breslow thickness and Clark's level were found to be significantly increased in excision versus incision biopsy specimens. Nine patients had differing mitotic rates which were all higher in the excision biopsy samples. Conclusion: Our data supports the UK national guidelines on the management of malignant melanoma in that incisional biopsies are not indicated in the diagnostic pathway of malignant melanoma.