JAMES M.GRICHNIKMD, PhD
The lesions are from the right arm of a 53-year-old man (Figure 1), the left leg of a 57-year-old woman (Figure 2), and the left arm of a 48-year-old man (Figure 3) (size bar, 3 mm) affected with a disseminated superficial actinic porokeratosis. All 3 lesions reveal a similar pattern. A “white track” structure can be identified at the periphery of the lesion with a brownish pigmentation in the inner side and with “double white track” in some parts of the lesion. This structure is characteristic of porokeratosis. The images in Figure 1 and Figure 2 reveal red dots, globules, and lines in the center of the lesion; however, the lesion in Figure 3 shows a white homogeneous area. The single or double “white track” structure at the margin corresponds to the cornoid lamella, and the red dots, globules, and lines are enlarged capillary vessels that can be observed because the epithelium is atrophic. The white homogeneous area in the center of the third lesion corresponds to acanthotic epithelium, which can be rarely observed in these lesions.
Zaballos P, Puig S, Malvehy J. Dermoscopy of Disseminated Superficial Actinic Porokeratosis. Arch Dermatol. 2004;140(11):1410. doi:10.1001/archderm.140.11.1410