Benign vascular invasion in vasitis nodosa.

Vasovasostomy specimens were examined for vascular changes in 50 cases of vasitis nodosa. In five, benign gland- or ductule-like structures were seen invading small veins and, in one, also the small arteries. The intravascular ductules appeared benign, and there was no clinical evidence of malignancy. The presence of ductules in the blood vessels always was accompanied by marked elastosis. In 12 additional cases, elastosis of arteries and veins was seen without intravascular ductules. These changes suggest that proliferating ductules in vasitis nodosa invade the blood vessels after they have become obliterated by regressive and reparative processes.