A 89-year-old woman consulted for a pigmented lesion on her forehead. A basal cell carcinoma was the main clinical diagnosis.
On this picture, with a slight pressure of the dermoscope (polarized light dermoscopy), arborizing blood vessels are well seen.Blue gray dots and globules are the other dermoscopic signs in favor of this basal cell carcinoma.
If the pressure of the dermoscope is too important, the blood vessels are not visible.Vessels and red areas are better visualized with polarized light dermoscopy than with immersion contact dermoscopy (1)
References:
1 - Marghoob et al. Differences between polarized light dermoscopy and immersion contact dermoscopy for the evaluation of skin lesions. Arch Dermatol 2007 Mar;143(3):329-38