Narrow-margin excision is a safe, reliable treatment for well-defined, primary pigmented basal cell carcinoma: an analysis of 288 lesions in Japan

BACKGROUND: Complete excision is the most promising treatment for basal cell carcinoma (BCC) and a surgical margin of at least 4 mm is recommended. However, little is known about the appropriate surgical margin of pigmented BCC.

OBJECTIVE: To investigate the reliability of narrower margin excision of well-defined, pigmented BCC.

METHODS: We identified a total of 263 patients with 288 well-defined, primary pigmented BCC at the Department of Dermatology, Kyushu University (Fukuoka, Japan), between January 2006 and December 2013. All lesions were surgically excised with 1-6-mm margins and analysed. For 30 recent lesions out of the 288 lesions, border gaps between dermoscopy and histopathology were assessed.

RESULTS: Of the 288 lesions, 218 (75.7%) were excised with a narrow margin (≤ 3 mm) and 60 lesions (24.3%) with a wide margin (≥ 4 mm). Only two lesions (0.7%), which were excised with 2-mm margins, were associated with tumour-positive margins. Narrow-margin excision showed a complete removal rate of 99% (2-mm margins, 95.3%; 3-mm margins, 100%). Dermoscopically determined borders almost exactly corresponded to the histopathological ones; 71.2% of border gaps between dermoscopy and histopathology were within 1 mm and there were no cases in which tumours spread beyond 1 mm of their dermoscopic borders.

CONCLUSION: Surgical excision with a 2-3-mm margin is reliable treatment for well-defined, primary pigmented BCC, with a complete removal rate of 99%.