Pseudoxanthoma elasticum-like papillary dermal elastolysis: immunohistochemical study using elastic fiber cross-reactivity with an antibody against amyloid P component.

Pseudoxanthoma elasticum (PXE)-like papillary dermal elastolysis is a rare disorder clinically characterized by multiple, asymptomatic nonfollicular papules, yellow or flesh colored, grouped to form plaques with cobblestone appearance. These plaques are arranged symmetrically on the neck and supraclavicular areas of adult or elderly women, closely resembling the lesions of PXE. Histopathologically, the lesions are characterized by a band-like area of elastolysis along the papillary dermis. We report 2 cases of PXE-like papillary dermal elastolysis, in which the anomalies of the elastic tissue were immunohistochemically investigated with an antibody to the amyloid P component. This immunostaining demonstrated a band-like loss of elastic tissue along the papillary dermis. No clumping, fragmentation, or calcification of the elastic tissue was seen. We also review the literature about this rare process and discuss the differential diagnosis with other elastic tissue disorders that may show similar clinical and/or histopathologic findings.