Morphological Patterns Identification in PET+ Aneurysmatic Lesions

The size of abdominal aortic aneurysm (AAA) is a well-known risk factor, predictive for rupture. The employment of Positron Emission Tomography (PET) has recently proven to be helpful in determining which AAA are at imminent risk of rupture. We applied our macroscopic sampling and histological examination protocol to I4 AAA (2 of which PET positive), in order to determine the correlations between metabolic activation of the aneurysmal wall and histomorphological findings. Our aim is to obtain a better understanding of the pathogenesis of AAA rupture and to provide a further contribute in their diagnostic evaluation. We applied our histochemical protocol (Hematoxylin-Eosin (HE), Alcian Blue (pH-I), PAS, Masson Thrichromic and Weigert) on aortic aneurysm specimen and evaluated the proliferative index by immunohistochemistry (Ki-67/MIB-I) in order to detect any relationship between PET negative aortic specimen showed follicular lymphocytic aggregatesm especially located within the advated proliferative index (Ki-67) of the flogistic aggregates in our two groups (PET positive and PET negative). We believe that further IHC investigations with enzymes that are well-known implied in AAA pathogenesis (i.e. MMP-8 and MMP-9) should provide more accurate information in predicting the risk of rupture.