Difference between pigmented and nonpigmented basal cell carcinoma treated with mohs micrographic surgery

BACKGROUND There have been several articles characterizing cases of pigmented basal cell carcinomas (PBCC). Previous studies have also evaluated the relationship between histologic pattern and frequency of basal cell carcinoma (BCC) associated with pigment formation. No specific studies, however, have examined the subclinical extension and surgical margins of PBCC tumors. OBJECTIVE A prospective study of 345 Mohs micrographic BCC surgical cases revealed 67 PBCC cases. Analysis of patient details included patient age and sex, the lesional site, histologic subtype, tumor size, final surgical margin, and the number of stages required to achieve tumor-free margins together with the presence or absence of pigment. METHODS This study was performed between May 2004 and January 2005 at the Department of Dermatology and Cutaneous Surgery, University of Miami, Mohs Surgery Center. RESULTS Total mean surgical margin was smaller in the PBCC than the nonpigmented BCC (NPBCC) group (3.89 mm vs. 5.85 mm; p < 0.05). In lesions less than 2 cm in size, there were even more significant differences between the two groups (3.32 mm vs. 5.33 mm; p < 0.05), and also between the aggressive and nonaggressive histologically diagnosed groups (3.13 mm vs. 5.01 mm; p < 0.05). CONCLUSIONS We have demonstrated that PBCC requires a smaller surgical margin for complete tumor excision than NPBCC, especially in smaller tumors and in the nonaggressive histologic subtype group. Treatment within the early growth stages also involves less subclinical microscopic invasion and a smaller surgical margin in PBCC.