Histologic changes in thromboangiitis obliterans

Three phases of thromboangiitis obliterans have been described pathologically. In the acute phase (shown above), occlusive inflammatory thrombus develops within the vessel. Polymorphonuclear leukocytes, microabscesses, and multinucleated giant cells may also be present. The intermediate phase is characterized by progressive organization of the thrombus. In the chronic phase, only organized thrombus and fibrosis remain; the inflammation is no longer present.