[Mönckeberg's sclerosis -- crystal-induced angiopathy]

Mönckeberg's sclerosis is a special form of arteriosclerosis characterized by calcification and ossification of the media of medium size arteries mainly of lower extremities.

The aim of the authors was to examine medium size arteries with Mönckeberg's sclerosis in 22 amputated lower legs of 16 patients in order to demonstrate different crystals in the wall of blood vessels.

The methodology was based on previous findings of the authors indicating that in different metabolic disorders many crystals remain demonstrable in unstained histological sections unlike in haematoxylin-eosin stained sections.

In unstained sections the authors observed rhomboid or prismatic calcium pyrophosphate dihydrate and clusters of elongated narrow hydroxyapatite crystals in the wall of medium size arteries of all examined cases. Both types of crystals showed axis parallel positive birefringence under polarized light. The intensity of birefringence of hydroxyapatite crystals was weaker in comparison with that of calcium pyrophosphate dihydrate crystals. Occasionally, other crystals which were different in shape from both calcium pyrophosphate dihydrate and hydroxyapatite crystals were also observed.

It seems likely that similarly to crystal deposition induced arthropathy, calcium pyrophosphate dihydrate, hydroxyapatite and other crystals cause fibrosis and intimal proliferation, which may contribute to progressive occlusion of blood vessels resulting in ischemic symptoms. Based on this observation Mönckeberg's sclerosis may be defined as a crystal-induced angiopathy.