Features of regression in dermoscopic diagnosis: a confounding factor? Two clinical, dermoscopic-pathologic case studies.

Background: In dermoscopy, the presence of regression areas is generally associated with melanocytic lesions and is often considered a clue of malignancy. However, some lesions included in the differential diagnosis of melanoma may show dermoscopic regression parameters. Regression may indeed be one of the most confounding dermoscopic parameters because it tends to cover, or rather to destroy, other parameters, thus often hindering a correct diagnosis.

Objective: We propose to raise the issue of the actual diagnostic role of this parameter.

Methods: We discuss two clinical cases (melanoma and basal cell carcinoma) with major dermoscopic regression features.

Conclusion: Dermoscopic regression parameters should not be regarded as almost pathognomonic signs of melanocytic lesions. Rather, they should be taken into account only after having considered other dermoscopic parameters of greater diagnostic significance and just as signs that may better typify the lesion.