[Elastosis perforans serpiginosa in a patient with pseudoxanthoma elasticum].

A 34-year-old female previously diagnosed of pseudoxanthoma elasticum developed an annular plaque with serpiginous borders of 42 by 30 mm in diameter on the inner left arm. A similar lesion later appeared on the inner right arm. Histopathological examination of a papule showed short, fragmented, granular, basophilic and calcified elastic fibers in the mid-reticular dermis. The epidermis showed hyperplasia surrounding degenerated and normal elastic fibers. Transepidermal elimination channels of these elastic fibers were also observed. These findings were consistent with the diagnosis of elastosis perforans serpiginosa. Abundant multinucleated giant cells were observed surrounding the area of epidermal hyperplasia and in the reticular dermis. The patient was treated with tazarotene, and the plaques disappeared in 9 months.