A Case of Lower GI Bleeding Caused by Localized Amyloid Light-Chain Amyloidosis in the Small Intestine

Abstract

Introduction: Amyloidosis is a disorder characterized by the abnormal deposition of extracellular amyloid fibrils that leads to disruption of tissue structure. Systemic amyloidosis can involve the gastrointestinal tract. The small intestine is the most commonly involved gastrointestinal site. However, cases of localized amyloid light-chain amyloidosis in the small intestine are rarely reported. Here we report a case of primary amyloidosis only in the small intestine without any other organ involvement. Case: A 73-year-old male with history of alcoholic pancreatitis, hypertension was transferred to our hospital with complaints of hematochezia before 2 days ago. Laboratory tests revealed that serum hemoglobin level decreased from 11.6 to 7.7 g/dL. There was no bleeding focus on gastroduodenoscopic and colonoscopic examination. Contrast enhanced CT enterography for evaluation of small bowel bleeding showed that two sites of aneurysmal dilatation of small bowel loops with concentric wall thickening (Figure 1a, 1b). Balloon enteroscopy to examine the lesions in the small bowel detected cystic mucosal lesion with hemorrhagic surface change with easily touch bleeding below the 2nd portion of duodenum (Figure 2a). For control of bleeding, he underwent surgery of small bowel resection. There were 2 segmental lesions (5cm in the jejunum, 8cm in the ileum) of small bowel wall dilatation. Also small bowel between the lesions showed distended and edematous in the operation finding (Figure 2b). Histologic examination of the specimen revealed amyloid deposition (Figure 3a) and positive Congo red staining in the small intestine (Figure 3b). According to the results of immunohistochemistry, deposits of amyloid were positive for amyloid kappa (Figure 3c), lambda (Figure 3d), but negative for amyloid A. Therefore the results were indicative of amyloid light-chain (AL) amyloidosis. Bone marrow biopsy for evaluation of systemic amyloidosis founded that no definite evidence of plasma cell disorder. Serum and urine electrophoresis revealed no monoclonal gammopathy. There was no evidence of other organ involvement. In conclusion, he was diagnosed with localized AL amyloidosis in the small intestine. He was followed-up as an outpatient without history of re-bleeding and complaining of other symptom.Figure 1Figure 2Figure 3Conclusion: Localized amyloidosis in the small intestine can manifest the symptom of lower GI bleeding. Because our patient underwent resection of involved small intestine without any other treatment, it needs to follow-up about progression to systemic disease, re-bleeding and any other complications.