Segmental arterial mediolysis of the middle colic artery: report of a case with special reference to lesions of small arteries and veins

xlomafota13 shared this article with you from Inoreader Segmental arterial mediolysis of the middle colic artery: report of a case with special reference to lesions of small arteries and veins Via International Journal of Clinical and Experimental Pathology Int J Clin Exp Pathol. 2021 Apr 15;14(4):508-513. eCollection 2021. ABSTRACT We report a case of segmental arterial mediolysis (SAM) that involved the middle colic artery, and present some pathologic alterations found in mesenteric small arteries and veins. The patient, a 52-year-old woman, underwent an emergency laparotomy for acute intra-abdominal hemorrhage, and a segment of the transverse colon with hemorrhagic mesocolon was excised. Microscopic examination demonstrated two separate lesions of SAM in the middle colic artery. The involved arterial segments showed a partial to circumferential loss of the media (mediolysis) and intima associated with the formation of a pseudoaneurysm. Smooth muscle cells adjacent to the mediolysis showed various degenerative changes. In addition, we found multiple, tiny foci of degenerative lesions affecting the outer media in the wall of small arteries. Subendothelial vacuoles and nodular intimal pro liferation were also noted in small veins. Whereas SAM chiefly affects large or medium-sized arteries, small blood vessels, including veins, are also affected. The present case is unusual in that degeneration of medial smooth muscle cells was clearly observed in the arterial walls, and the small veins were affected by lesions similar to those in arteries. We suspect that a phenotypic modulation of vascular smooth muscle cells induced by some genetic vulnerability plays a role in the pathogenesis of SAM. PMID:33936374 | PMC:PMC8085823 View on the web Inoreader. Take back control of your news feed. Follow us on Twitter and Facebook.