Clinical pathologic observations in pseudoxanthoma elasticum.

Skin biopsy material obtained from 2 patients with pseudoxanthoma elasticum associated with congenital hyperphosphatasia was compared with skin biopsy material obtained from 3 patients with pseudoxanthoma elasticum unassociated with any other disease. Clinically normal skin showed calcification of normal-appearing elastin as the initial change in pseudoxanthoma elasticum. Elastin fibers become more ravelled as the disease progresses. A previously unreported early transient calcification of collagen was demonstrated. Other abnormal collagen forms may also be present. The Von Kossa stain appears to be the stain of choice for identifying these earliest histologic changes.