背景:淀粉样变是一种罕见的疾病,其特征是错误折叠的蛋白质聚集成不溶性原纤维的细胞外沉积。全身性淀粉样变性的胃肠道受累是常见的,但通常是亚临床或表现为模糊和非特异性症状。在系统性淀粉样变性患者中,胃肠道症状是罕见的主要症状,导致它直到晚期疾病才被诊断出来。
方法:一名53岁的男子腹泻,便血,并将体重减轻送到社区医院。当时的结肠镜活检可疑为克罗恩病。由于症状恶化,包括恶心,呕吐,和一个新的瘀点皮疹,进行了腹部脂肪垫活检。活检显示乳头状和附件真皮淀粉样蛋白沉积,通常在皮肤淀粉样变性中看到。然而,细胞角蛋白5/6为阴性,不包括皮肤淀粉样变性。结节性淀粉样变性的模式,皮下淀粉样蛋白沉积和血管周围淀粉样蛋白未见。高碘酸-希夫染色对类脂蛋白沉积呈阴性,刚果红在偏振上对苹果绿双折射呈阳性,淀粉样蛋白分型证实了淀粉样蛋白轻链淀粉样变性。胃肠道的重复内镜活检显示淀粉样蛋白沉积从食道到直肠,在慢性炎症性疾病背景下的血清淀粉样蛋白A中常见的模式,包括严重的炎症性肠病.骨髓活检显示κ限制性浆细胞肿瘤。
结论:描述了原发性系统性淀粉样变性的不寻常表现,强调误诊的风险,随后显著的器官功能障碍和高死亡率。
BACKGROUND: Amyloidosis is a rare disease characterized by extracellular deposition of misfolded protein aggregated into insoluble fibrils. Gastrointestinal involvement in systemic amyloidosis is common, but is often subclinical or presents as vague and nonspecific symptoms. It is rare for gastrointestinal symptoms to be the main presenting symptom in patients with systemic amyloidosis, causing it to be undiagnosed until late-stage disease.
METHODS: A 53 year-old man with diarrhea, hematochezia, and weight loss presented to a community hospital. Colonoscopy with biopsy at that time was suspicious for Crohn disease. Due to worsening symptoms including nausea, vomiting, and a new petechial rash, an abdominal fat pad biopsy was done. The biopsy showed papillary and adnexal dermal amyloid deposition, in a pattern usually seen with cutaneous amyloidosis. However, Cytokeratin 5/6 was negative, excluding cutaneous amyloidosis. The patterns of nodular amyloidosis, subcutaneous amyloid deposits and perivascular amyloid were not seen. Periodic Acid-Schiff stain was negative for lipoid proteinosis, Congo red was positive for apple green birefringence on polarization and amyloid typing confirmed amyloid light chain amyloidosis. Repeat endoscopic biopsies of the gastrointestinal tract showed amyloid deposition from the esophagus to the rectum, in a pattern usually seen in serum amyloid A in the setting of chronic inflammatory diseases, including severe inflammatory bowel disease. Bone marrow biopsy showed kappa-restricted plasma cell neoplasm.
CONCLUSIONS: Described is an unusual presentation of primary systemic amyloidosis, highlighting the risk of misdiagnosis with subsequent significant organ dysfunction and high mortality.