DS27 Tangential shave excision is an effective and economical method for accurate diagnosis of suspicious macular pigmented lesions

Abstract

Multiple diagnostic methods exist for assessment of suspicious lesions; tangential shave excision is one example. This is most effective for macular pigmented lesions, whereby pathology is typically limited to the epidermis or superficial dermis, assessed with dermoscopy. Alternatives include elliptical and punch excisions. We aimed to assess the accuracy of the shave excision technique as a diagnostic tool for assessment of suspicious macular pigmented lesions. A retrospective review was undertaken of shave excisions of macular pigmented lesions in a single centre across a 10-year period from January 2014 to December 2024. Data were extracted from electronic patient records and histopathological reports, yielding 5533 cases. In total 253 cases of melanoma in situ (MIS), 123 invasive melanomas, 652 dysplastic naevi and 107 benign junctional naevi were identified; 4398 alternate diagnoses were excluded. One case of invasive melanoma (0.8%) was upstaged following wide local excision (WLE) preceded by deep margin transection; pT3a on the scalp to pT4a. Sentinel lymph node biopsy confirmed regional metastases. Five cases of MIS (2%) were upstaged following WLE: one with prior deep margin involvement (pT2a on the toe), two with peripheral involvement (shoulder lesion upstaged to pT2a and arm pT1a) and two MIS fully excised on the initial shave (pT1b on flank and pT1a temple). One dysplastic naevus (0.2%) with peripheral involvement was upstaged to focal MIS on WLE. Of the two cases of benign junctional naevi with deep margin involvement, neither was upstaged following WLE. Tangential shave excision facilitates accurate diagnosis of macular pigmented lesions when performed correctly. Risk of upstaging to invasive melanoma is low. It can be performed simply and economically at the time of the consultation. The lack of linear scar benefits decision making for orientation of the subsequent WLE should it be required.