Pseudoxanthoma elasticum: biopsy of clinically normal skin in the investigation of patients with angioid streaks.

Background: Pseudoxanthoma elasticum (PXE) is a genetic disorder characterized by fragmentation and calcification of elastic fibres with resultant pathological changes in the dermis, Bruch's membrane and blood vessels. Defects in Bruch's membrane produce angioid streaks on the retina but this appearance is not pathognomonic of PXE. Biopsy of clinically normal skin or scar tissue in patients with angioid streaks may show the histological features of PXE.
Objectives: To test the hypothesis that biopsy of clinically normal skin is a useful investigation in patients with angioid streaks.
Methods: This prospective study investigated 18 consecutive patients with angioid streaks. Each patient underwent a full dermatological examination and was investigated for diseases known to be associated with angioid streaks. Axillary skin biopsies were taken from 14 consenting patients.
Results: Typical PXE was found in 11 patients. No other diseases associated with angioid streaks were identified. Five patients had angioid streaks in the absence of systemic disease. Two patients had nondiagnostic dermatological features which were not clarified by histology. Two of the 11 patients with PXE showed histological evidence of PXE from clinically normal axillary skin. However, in both cases flexural skin elsewhere showed the typical clinical and histological features of PXE.
Conclusions: This study demonstrates the association between angioid streaks and PXE. However, it does not support the hypothesis that biopsy of normal-looking skin is helpful in the investigation of adult patients with angioid streaks.