Primary gastroduodenal amyloidosis.

position of insoluble fibrillar proteins in various organs [1]. In humans, more than 23 different and unrelated proteins are known to form amyloid fibrils [2]. Amyloidosis is divided into primary (i. e. idiopathic) and secondary amyloidosis (i. e. associated with chronic inflammatory conditions, and infectious and neoplastic disorders) [1]. Primary amyloidosis is extremely rare in the gastrointestinal tract. Fewer than 1% of patients with primary amyloidosis in the gastrointestinal tract have any symptoms [3]. We report a case of primary gastroduodenal amyloidosis in which endoscopic ultrasound (EUS) was instrumental in the work-up. A 76-year-old man presented with a history of fatigue, dyspepsia, and anemia. An upper-gastrointestinal endoscopy revealed prominent gastric folds and gastropathy (●" Fig. 1a). Gastric biopsies showed only signs of unspecific inflammation. The patient developed diarrhea andweight loss. Abdominal computed tomography (CT) showed unspecific gastric wall thickening. The initial suspicion was a malignant disease such as scirrhous carcinoma, which led to an EUS referral. EUS revealed gastric wall thickening (●" Fig. 1b) and a complete lack of normal sonographic layers in the stomach wall, suggestive of an infiltrative disease (●" Fig. 1b), but no sign of malignancy. Another upper-gastrointestinal endoscopy was undertaken with new biopsies from the stomach and bulbus duodeni. Congo red staining revealed amorphous eosinophilic infiltrates (●" Fig. 2a) and green birefringence under polarized light (●" Fig. 2b), which is diagnostic for amyloidosis [1]. It may be suggested that tissue deposition of insoluble proteins causes the sonographic disappearance of normal gastric wall layers in amyloidosis. This patient had no systemic disease such as a chronic immune disease or neoplastic disorder, which are the most common causes of secondary amyloidosis. Thus this patient had a primary amyloidosis in the gastroduodenum. In conclusion, this case highlights the use of EUS in the work-up of patients with suspected amyloidosis in the stomach and duodenum. Endoscopy_UCTN_Code_CCL_1AB_2AD_3AD