Pigmented basal cell carcinoma: investigation of 70 cases
At the time of publication, Mary E. Maloney was not yet affiliated with the University of Massachusetts Medical School.
BACKGROUND: Pigmented basal cell carcinoma (PBCC) is a clinical and histologic variant of BCC.
OBJECTIVE: Our purpose was to identify the histologic subtypes of BCC that were most often associated with pigment and to determine whether this correlated with outcome after excision.
METHODS: A series of PBCC was identified and the histologic subtype noted. Margins of all excisions were examined for residual tumor. These results were then compared with a series of nonpigmented BCCs.
RESULTS: In a series of 1039 consecutive BCCs, 70 (6.7%) contained pigment. The histologic growth pattern most frequently associated with pigment was the nodular/micronodular pattern (12.4%) followed by the nodular (7.7%), superficial (7.2%), micronodular (4.0%), and the nodular/micronodular/infiltrative (3.4%) patterns. Margins were examined for evidence of residual tumor in the 40 cases that were excised. In only one case (2.5%) was the margin positive for tumor. This was statistically significant (p less than 0.05) compared with 388 excisions of nonpigmented BCCs with comparable growth patterns in which 69 (17.7%) showed positive margins.
CONCLUSION: PBCC, as a clinical variant, is more frequently excised with adequate margins than are tumors of comparable histologic subtypes that do not contain pigment.