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[Pathological studies on microvasculature of arteriovenous malformation in the intestinal tract]
E Atari1, H Mitomi, M Okudaira
1Department of Pathology, School of Medicine, Kitasato University.
Abstract:
Intestinal arterio-venous malformation (AVM) is one of the uncommon causes of gastrointestinal hemorrhage and is usually difficult to diagnose before pathological study. Five operated cases with the AVM were presented. The vascular lesions were studied by barium-gelatin injection and routine histological procedures. The AVM lesion was detected in the proximal jejunum and in the distal ileum in each one case, respectively. In two other cases the AVM lesion was observed as a protruded tortuous vascular plexus in colonic mucosa. By the microangiographical study, it was confirmed that the main lesion of AVM was located in submucosal layer with complicating minute AVM in lamina propria of intestinal mucosa. In the mucosal lesion of AVM it was disclosed that arterialization of precapillary arterioles was a remarkable finding. Thickened intimal layer and duplication of internal elastic lamina were recognized in these arteriolar lesions. Two kinds of intestinal AVM were classified, one is located in the submucosal layer and another one is located in mucosal layer. It was suggested that a marked ectasia of mucosal vessels seemed to be a secondary change of the submucosal AVM. The pathogenesis of the mucosal AVM was discussed.
Insights
Intestinal arterio-venous malformations (AVMs) are rare causes of GI bleeding, often diagnosed post-surgery. This study classified AVMs into submucosal and mucosal types, detailing their unique vascular characteristics.
Area of Science:
- Gastroenterology
- Vascular Pathology
- Surgical Anatomy
Background:
- Intestinal arterio-venous malformation (AVM) is an uncommon cause of gastrointestinal hemorrhage.
- Diagnosis of AVMs is challenging prior to pathological examination.
Observation:
- Five surgically treated cases of intestinal AVMs were analyzed.
- Vascular lesions were studied using barium-gelatin injection and histology.
- AVMs were identified in the jejunum, ileum, and colon.
Findings:
- Microangiography revealed submucosal AVMs with mucosal involvement.
- Mucosal AVMs showed arterialization of precapillary arterioles with thickened intima and duplicated elastic laminae.
- Two distinct types of intestinal AVMs were classified: submucosal and mucosal.
Implications:
- Mucosal AVMs may represent secondary changes related to underlying submucosal AVMs.
- Understanding AVM classification aids in diagnosis and treatment strategies.
- Further research into the pathogenesis of mucosal AVMs is warranted.