“…Tissue specimens seldom included the acute phase lesion, which Buerger viewed as essential for diagnosis. 1,11,12 Chronic lesions, often said to be the least distinctive of the three stages of Buerger's disease, may be merely nonspecific residual evidence of arterial occlusion. 3,4,13 We examined all three stages by means of immunohistochemistry to determine which stage (acute, subacute, or chronic) possesses distinctive features.…”