AL-amyloidosis of the small intestine complicated by massive bleeding; [AL-амилоидоз тонкой кишки, осложнившийся массивным кровотечением]

Background. As known gastrointestinal amyloidosis is an uncommon disorder. Bleeding caused by amyloid deposition in the wall of small intestine vessels is one of the severe and serious complications of gastrointestinal amyloidosis associated with multiple non-specific clinical manifestations. Misdiagnosis and inadequate treatment of acute bleeding could lead to a lethal outcome. To present a case report of the patient with amyloidosis of the small bowel that manifested as massive intestinal bleeding and was initially misdiagnosed as multiple vascular malformations of the small intestine. Methods and results. A 60-year-old patient was admitted to the gastroenterology department complaining of epigastric pain and black stooL Esophagogastroduodenoscopy and enteroscopy revealed an area of dense off-white infiltrated mucosa with accentuated vascular pattern and damage problems of the mucosal surface caused by scope passage. Biopsy specimen was taken for pathological verification of diagnosis and tattoo of the defect was performed. Pathomorpho-logical assessment included Congo red staining that highlighted the eosinophilic material in the proper mucous plate, adjacent submucous layer and in the vascular walls which showed apple-green birefringence under polarized light typical for amyloid. Immunohistochemical typing of amyloid revealed a positive reaction with the antibody against amyloid P-component and AL-lambda amyloid. Conclusion. The presented clinical case has demonstrated the complexity and versatility of diagnosing amyloidosis of the small intestine. © 2023 GEOTAR Media. All rights reserved.