Recurrent basal cell carcinoma following ablative laser procedures.

Background: In Korea, many patients diagnosed with basal cell carcinoma (BCC) have a history of laser ablations of undiagnosed lesions.

Objective: To evaluate the clinical/pathological and surgical features of BCC developing from undiagnosed lesions following laser ablations (not full-face cosmetic ablations) and to compare them with primary BCCs.

Methods: This study enrolled 359 patients with 373 biopsy-proven BCC lesions. All of the patients were treated by Mohs micrographic surgery (MMS) at the Department of Dermatology, Pusan National University Hospital from 1998 to 2008. BCC was classified by previous treatment history of lesion ablative laser: post-laser BCC vs primary BCC. We conducted a retrospective study through clinical photographs, pathology slides, and MMS sheets.

Results: Among 373 BCCs, 58 lesions (15.5%) were post-laser BCCs. The post-laser BCC group was younger (59.9 vs 65.4 years, P = .001), but had a longer disease interval until pathologic diagnosis (7.18 vs 3.33 years, P < .0001) than the primary BCC group. The post-laser BCC group had a greater frequency of the micronodular pattern (22.4% vs 10.8%, P = .01), required more stages of excision (2.69 ± 1.63 vs 2.15 ± 1.05, P < .001), and had fewer cases with one Mohs stage excision (10.3% vs 27%, P = .006) than the primary BCC group.

Limitations: We could not identify the type of laser used in all 58 cases; instead, we supposed that most of the patients were likely treated with the carbon dioxide laser.

Conclusions: The results demonstrated that the post-laser BCC group had a longer disease interval to diagnosis, a more aggressive histologic pattern, and required more stages of excision in MMS than the primary BCC group.