Endoscopic features of gastrointestinal amyloid light-chain amyloidosis

A 48-year-old woman presented with chronic abdominal pain, loss of appetite, and weight loss. Upper endoscopy revealed a diffuse thickened mucosa of the stomach and duodenum (figure, A). Evaluation of gastric mucosa with narrow-band imaging and near focus showed a complete distortion of the mucosal surface pattern and aberrant microvasculature (figure, B). Haematoxylin and eosin staining of gastric and duodenal biopsies revealed an intense atrophy of the mucosa with thick eosinophilic tissue that completely infiltrated the lamina propria (figure, C). Congo red staining revealed a thick subendothelial band of amyloid (figure, D) and an immunohistochemical assay with monoclonal antibodies against amyloid kappa and lambda light chains showed a restriction in the expression of the lambda light chains in the amyloid. In addition, under polarised light microscopy the amyloid showed an apple-green birefringence characteristic of the protein. Flow cytometry was negative for lymphoma. A CT scan showed gastric, enteric, and colonic wall thickening, with multiple mesenteric lymphadenopathies. A substantial increase in kappa concentration (319·5 mg/dL) compared with lambda concentration (18·3 mg/dL; ratio 17·45) was observed in a serum-free light-chain assay. Bone marrow biopsy showed pathologically increased plasma cells. A diagnosis of primary amyloid light-chain amyloidosis was made. The patient was treated with bortezomib, with a favourable clinical evolution in the subsequent 6 months after the start of treatment, requiring parenteral nutritional support, improving her weight and nutritional parameters. Features of gastrointestinal amyloidosis – Authors’ replyWe appreciate Akira Hokama and Jiro Fujita's interest in our Clinical Picture,1 and thank them for their comments. We agree that the pattern of amyloid deposition might be associated with more specific clinical and endoscopic findings. Light-chain amyloid deposition is usually seen in the muscularis mucosa, submucosa, and muscularis propria, often resulting in polypoid protrusions, and has been described to present with symptoms of intestinal obstruction. Amyloid A protein deposition is mainly seen in the mucosa, which can lead to increased friability and erosions in the affected area, most often presenting with diarrhoea and clinical features of malabsorption. Full-Text PDF Features of gastrointestinal amyloidosisWe read with great interest the Clinical Picture by Latorre and colleagues,1 which described the endoscopic features of gastrointestinal amyloid light-chain amyloidosis. We commend the authors for this valuable contribution; however, their explanation of clinical and endoscopic features of this type of amyloidosis appears to have been confused with those of amyloid A protein amyloidosis, which is usually caused by chronic systemic inflammatory disorders. Full-Text PDF