The lesions are from the back of a 69-year-old woman (Figure 1), the dorsal surface of the left hand of an 82-year-old woman (Figure 2), the chest of a 75-year-old man (Figure 3), and the chest of a 72-year-old man (Figure 4). All 4 lesions reveal the presence of blue-gray localized coarse granules (arrowheads) typical of benign lichenoid keratosis (BLK). The pattern is similar to lichenoid regressing seborrheic keratosis, as noted previously,1 and supports the concept that BLK is a regressive response to a preexisting skin tumor. These 4 cases illustrate the intermediate stage of this phenomenon in solar lentigines. It is important to dermoscopically distinguish BLK from regressing melanoma. In melanomas, the blue-gray granules may be finer and more multifocal but it is likely that other dermoscopic patterns will help identify the melanomas. For lesions of concern, a biopsy is necessary to confirm the diagnosis.
Zaballos P, Rodero J, Pastor L, Vives JM, Puig S, Malvehy J. Dermoscopy of Lichenoid Regressing Solar Lentigines. Arch Dermatol. 2008;144(2):284. doi:10.1001/archdermatol.2007.61