Anesthetic Blister Formation for Biopsy-Site Identification Prior to Mohs Micrographic Surgery

Confirming biopsy sites before Mohs micrographic surgery can be difficult when wounds have healed clinically and documentation is limited, risking wrong-site surgery. We describe a simple intraoperative adjunctive technique: a focal blister that may form at a recent biopsy site during slow intradermal local anesthetic infiltration. This finding may reflect transient immaturity of anchoring fibrils during early wound remodeling and appears to occur most often within the first few weeks after biopsy. Although it requires no extra equipment and can help confirm a carefully chosen presumptive site, it should be used only as an adjunct to standard evaluation, not as proof or a reason to inject multiple sites. Prospective studies are needed to define its accuracy and optimal timing.