Diagnosis of pseudoxanthoma elasticum by scar biopsy in patients without characteristic skin lesions.

Pseudoxanthoma elasticum is a disorder of connective tissue that is associated with numerous systemic complications, including accelerated atherosclerosis, gastrointestinal bleeding, angioid streaks in the ocular fundus, and blindness. Diagnosis of the disease is important because many of its complications can be prevented and genetic counseling can be offered to family members of affected patients. The purpose of this study was to examine the usefulness of scar biopsy in establishing a diagnosis of pseudoxanthoma elasticum in patients with angioid streaks but without characteristic skin lesions. Ten patients with angioid streaks but without cutaneous findings indicative of pseudoxanthoma elasticum were evaluated by biopsy of scars and flexural skin. The biopsy specimens were compared with those from unaffected controls. In 6 of the 10 patients, scar biopsies showed fragmentation and clumping of elastic tissue in the deep dermis. Three patients also had these histologic features of pseudoxanthoma elasticum in biopsy specimens of flexural skin that appeared to be normal. We conclude that biopsies of scars in randomly chosen sites may be useful when pseudoxanthoma elasticum is suspected despite the absence of typical skin lesions.