History of laser ablation in pigmented basal cell carcinoma conceals classic dermoscopic patterns.

BACKGROUND: Some patients with pigmented basal cell carcinoma (pBCC) had a history of laser ablation after misdiagnosis, which may conceal the dermoscopic clues of malignancy. OBJECTIVE: The objective of this study was to investigate the question of whether the classic and nonclassic dermoscopic patterns of BCCs may be concealed by past laser ablation. METHODS: Classic and nonclassic dermoscopic patterns were examined in 55 pBCC patients with a history of laser ablation and another 150 control pBCC patients. RESULTS: All but 4 of the study patients (92.3%) showed at least 1 classic pattern of BCC, whereas every control patient showed more than 1 classic pattern (p = .995). Compared with the control group, the detection rate of large blue/gray ovoid nests, multiple blue/gray globules, and ulceration was found to be significantly decreased in the study group (p < .05). However, 4 patients who lacked classic patterns showed at least 1 nonclassic pattern. CONCLUSION: Previous laser ablation in pBCC may conceal the classic dermoscopic patterns by reducing the detection rate. Therefore, more prudent and detailed dermoscopic monitoring is required in suspected cases of pBCC, especially in patients with a history of laser ablation.