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THU0456 The clinico-histopathological algorithm for differential diagnosis of buerger’s disease, takayasu arteritis and atherosclerotic occlusive disease

Background Arterial occlusive disease is a significant cause of the disability due to lower limbs amputations. In addition to atherosclerosis, systemic vasculitides can present with progressive critical limb ischemia and could be misdiagnosed as atherosclerotic occlusive disease. Objectives To investigate the pathological findings in vessels of the lower limbs amputated due to Takayasu arteritis (TAK), Buerger’s disease (BD) in comparison to atherosclerotic occlusive disease (AOD) and diabetic angiopathy (DA). Additionally, to develop an algorithm for clinico-histopathological differential diagnosis. Methods The specimens of vessels segments were obtained from the nine anatomical levels of amputated lower extremities in 132 patients, of which 30 were with TAK, 42 with BD, 30 with AOD and 30 with DA. Results In cases of BD, the exudative-productive endo-mesoarteritis with intimal hyperplasia from stenosis to complete obliteration have been found in the lower leg and foot arteries. No morphological abnormalities were observed in proximal arteries above knee. The pathologic hallmark of BD was panphlebitis with intimal hyperplasia, most often in anterior and posterior tibial veins, vena dorsalis pedis and superficial vein. The most remarkable finding in cases of TAK was mesoarteritis and luminal narrowing due to the reactive intimal hyperplasia in proximal arterial segments. In approximately half of the cases, TAK was not diagnosed clinically and identified only based on the pathological examination. The most common incorrect clinical diagnosis was atherosclerotic occlusive disease. In seven cases of TAK, concomitant premature atherosclerosis of varying severity was observed. Interestingly, in our series of cases of TAK, males were most frequently affected. The correct clinical diagnosis of TAK was made in all females’ cases. It seems to be a trend to miss the clinical diagnosis of TAK in men. In cases of AOD, pathological examination revealed stenotic atherosclerotic plaques occurred most prominently in the tunica intima of femoral and popliteal arteries. The most common morphologic features in cases of DA were media calcinosis and fibrous lipid plaques both distal and proximal arterial segments. The algorithm for clinico-histopathological differential diagnosis of TAK, BD, AOD and DA consists of the following: a) the best diagnostic performance can be obtained with four-five specimens of the magistral vessels from the proximal and distal parts of the amputated limb and the superficial vein at the level of the upper third of the shin; b) using routine and special staining techniques (H and E, Masson’s trichrome stain for collagen fibres, Hart’s elastin stain); c) analysis of the demographic and clinical data; d) interpretation of pathologic changes in vessels of the lower limbs; e) making a pathologic diagnosis. Conclusions The current findings could contribute to the improving the differential diagnosis of Takayasu arteritis, Buerger’s disease, atherosclerotic occlusive disease and diabetic angiopathy. Disclosure of Interest None declared