Dermoscopic and Histopathologic Analysis of the Correlation between the Pigmentation of Basal Cell Carcinoma and Tumor Aggressiveness.

Background: Basal cell carcinoma (BCC) is the most common type of skin cancer. In patients with darker skin, most BCCs are pigmented. Studies suggest that increased pigmentation in BCC may be inversely associated with tumor aggressiveness.

Objective: This study analyzed the dermoscopic features and histopathologic patterns of BCCs to evaluate the correlation between BCC pigmentation and tumor aggressiveness.

Methods: A total of 76 BCC lesions were included in this retrospective study. The Mohs micrographic surgery (MMS) stage and tumor depth were measured as indices of tumor aggressiveness. The Fontana-Masson stain was performed for the identification of melanin, and immunohistochemical analysis was performed using Melan-A and HMB-45 to identify melanocytes.

Results: In MMS stage 1, the dermoscopic pigmentation value was 34.48%±14.22% (mean±standard deviation). In MMS stages 2 and 3, dermoscopic pigmentations were 13.72%±7.54% and 15.50%±17.52%, respectively. In the logistic regression model, higher dermoscopic pigmentation (95% confidence interval [CI], 0.68~0.99), melanin (95% CI, 0.63~0.89), and melanocyte-stained areas (95% CI, 0.70~0.92) were associated with a lower possibility of BCC tumor infiltration over the middle and lower layers.

Conclusion: We found an inverse correlation between the pigmentation and aggressiveness of BCCs. Clinicians can predict the subclinical infiltration depth of BCC on the basis of the pigmentation observed on dermoscopy. Pigmentation can be considered a favorable prognostic factor for BCC.