Histologic comparison of normal and diseased skin in patients with suspected calciphylaxis

The pathophysiology of calciphylaxis and histologic criteria for diagnosis are uncertain.

To address this, histology was compared in both diseased and normal skin from patients with suspected calciphylaxis.

Biopsies from 18 patients with suspected calciphylaxis were examined for vascular calcification, thrombosis, and intimal hyperplasia as well as extravascular calcification.

All but 2 patients were receiving dialysis, half had diabetes, half were treated with warfarin, and almost all had involvement of the thigh. Small artery or arteriole calcification was present in 11 lesional samples (56%) and 8 control samples (44%), including 4 patients with calcification in both. Calcification was coarse in 6 lesional samples but none of the controls (P = .02). Thrombosis (50%; P = .001) and intimal hyperplasia (39%; P = .008) were seen only in lesional tissue. Of the 9 samples with thrombosis, vascular calcification was observed in 8. Intimal hyperplasia was accompanied by vascular calcification in 6 of 7 samples and by thrombosis in 6 of 7. Extravascular calcification was present in both lesional tissue and control tissue.

Small study size.

Vascular calcification alone lacked specificity. Thrombosis and intimal hyperplasia in conjunction with more severe vascular calcification were specific findings, suggesting a pathogenic role.