Microcirculatory segments identified with monoclonal antibody against alpha-smooth muscle actin: comparison between Kimura's disease and angiolymphoid hyperplasia with eosinophilia.

Microcirculatory systems, which can be divided into several segments, have crucial physiological functions. We investigated whether monoclonal antibody against alpha-smooth muscle actin (alpha SMA) was useful for the identification of microcirculatory segments, according to the structure of their periendothelial cells, in two pathological cutaneous conditions. We examined skin specimens from patients with Kimura's disease and with angiolymphoid hyperplasia with eosinophilia, since little information is available on microvascular segments in these conditions. Immunostaining for alpha SMA revealed the morphological characteristics of the periendothelial cells clearly enough to identify five segments in the proliferative microvessels of Kimura's disease and angiolymphoid hyperplasia with eosinophilia. In Kimura's disease, postcapillary venules were predominant, while each vascular segment in angiolymphoid hyperplasia with eosinophilia was uniform. Vessels without periendothelial cells were detected to a greater extent in angiolymphoid hyperplasia with eosinophilia than in Kimura's disease. The antibody against alpha SMA appeared to be useful in the observation of periendothelial cells for the identification of vascular segments in pathological cutaneous conditions.