Is a biopsy needed to make the diagnosis of Thromboangiitis Obliterans?
Pathologic specimens are not commonly obtained during the acute phase of TO. Reluctance to obtain biopsy specimens of these vessels is because the distal extremity is usually ischemic and biopsy may lead to new ulceration. Therefore, most pathologic specimens come from amputated limbs. In the acute phase, a panvasculitis with a highly cellular thrombus with microabscesses in the thrombus and vessel wall are seen. In the subacute phase, the thrombus is less cellular and recanalization of the thrombus is apparent. There may be perivascular fibrosis during this phase. In the late phase, there is often organized and recanalized thrombus and perivascular fibrosis. Unlike other medium-vessel vasculitides, the internal elastic membrane is preserved and venulitis is frequently found.
