Reliability of skin biopsies in determining accurate tumor margins: A retrospective study after mohs micrographic surgery

Abstract

BACKGROUND: Skin biopsy reports of basal cell carcinoma and squamous cell carcinoma are often accompanied by comments on the margins. A physician's management can be influenced by such reports, particularly when the margins are reported as clear and no further interventions are pursued. OBJECTIVE: To retrospectively review pathology margins on Mohs micrographic surgery (MMS) cases performed at a University Center and to compare biopsy margins with the Mohs margins found on the first stage. MATERIALS AND METHODS: Data collection of 1,000 cases of Mohs surgery was obtained regarding margins on skin biopsy and compared with margins on the first stage of MMS. RESULTS: Overall, of the biopsies that showed only deep margin involvement, a lateral margin was seen on 32% of the first stages of MMS. Conversely, of the biopsies that showed only lateral margin involvement, a deep margin was seen on 14% of the first stages of MMS. Of the biopsies that showed clear margins, a margin was seen in 30% of the cases on the first stage of MMS. CONCLUSION: Skin biopsies processed through the bread-loafing technique are not reliable in detecting accurate margins, and therefore, a biopsy report should not include margin involvement within it. © 2014 by the American Society for Dermatologic Surgery, Inc.