A 4-mm surgical margin of clinically normal skin is the current standard for elliptical excision of basal cell carcinomas (BCCs). However, a 4-mm surgical margin is often not feasible on the face because of cosmetic and functional concerns. As such, facial excisions of BCCs are typically performed with the appropriate margin determined by the surgeon based on clinical features of the tumor.

We designed a study to test the efficacy of narrow-margin elliptical excisions for the treatment of small, well-demarcated facial BCCs.

A total of 134 primary, small (<1 cm), well-demarcated, facial nodular BCCs were excised as an ellipse with 1-, 2-, or 3-mm margins around the visible border of the tumor. The margin used was decided by the dermatologic surgeon based on cosmetic, anatomic, and functional factors, with the goal of clearing the tumor in a single excision. Using the Mohs technique for elliptical specimens, frozen sections were prepared and examined microscopically to provide complete histologic margin control.

In all, 134 facial BCCs were included in the study. On average, the tumors measured 0.6 × 0.5 cm. Of these, 27 (20.1%) had positive margins, requiring additional excision. Excisions with 1-, 2-, and 3-mm margins were associated with positive margins in 16%, 24%, and 13% of tumors, respectively. There was no statistically significant difference in the occurrence of positive margins based on tumor size, anatomic location, or the measured margin used.

Narrow margins (1-3 mm) are inadequate for the excision of small, well-demarcated, primary nodular BCCs of the face. To avoid repetitive operations and the risk of recurrence in anatomically sensitive areas, these tumors should be treated with standard wide margins (eg, 4 mm), or have Mohs micrographic surgery for histologic margin control.