Gastrointestinal amyloidosis mimicking gastric cancer. Case report and literature review

Résumé fourni par la source

Gastrointestinal amyloidosis is a rare condition characterized by nonspecific clinical manifestations and a variable endoscopic presentation, which allows it to mimic other gastrointestinal diseases, particularly gastric cancer. This article presents a clinical case of gastric and duodenal amyloidosis in a 38-year-old patient with untreated HIV infection, in whom the disease sequentially masqueraded as acute abdominal pathology, sepsis, and a neoplastic gastric process. The patient was admitted with complaints of severe epigastric pain, fever, and generalized weakness. Acute pancreatitis or peptic ulcer disease was initially suspected; however, laboratory and instrumental findings did not support these diagnoses. Computed tomography revealed thickening of the walls of the gastric antrum and duodenum, as well as generalized lymphadenopathy. Endoscopic examination demonstrated diffuse hyperemia, edema, contact and spontaneous bleeding of the gastric mucosa, circumferential infiltration, and multiple polypoid lesions, raising suspicion of a malignant tumor. The final diagnosis was established only after histopathological examination of biopsy specimens. Massive deposits of amorphous eosinophilic material were identified in the mucosa of the stomach, duodenum, and major duodenal papilla, showing positive Congo red staining and characteristic birefringence under polarized light, confirming amyloidosis. This case highlights that gastrointestinal amyloidosis should be considered in the differential diagnosis of infiltrative gastric lesions, especially in patients with immunodeficiency. Morphological verification using Congo red staining remains crucial for establishing the correct diagnosis and preventing misinterpretation of the condition as a neoplastic process.

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