Amyloidosis is the extracellular deposition of amyloid fibril protein in any tissue or organ. The clinical manifestations of pulmonary amyloidosis are variable and without specific symptoms. We report a rare case of diffuse alveolar septal amyloidosis which is an extremely rare pattern of involvement, with a very poor prognosis, to improve our understanding of the disease. A 27-year-old man complained of shortness of breath and cyanosis. High-resolution computed tomography revealed diffuse ground-glass opacifications with interlobular septal thickening in both lungs. The immune-histochemistry showed monoclonal lambda light chains. This case also showed nephrotic syndrome and cardiac arrhythmia, suggesting an involvement of the kidney and the heart. Diagnosis: The diagnosis was finally established by tru-cut transthoracic sonar guided lung biopsy (TSLB), and histological examination revealed Congo red-positive amorphous eosinophilic deposits in the alveolar sept. Interventions: The patient was admitted to a respiratory intensive care unit and put on non-invasive ventilation, then discharged on domiciliary oxygen therapy, and started treatment with chemotherapy melphalan 2 mg daily plus prednisone 60 mg daily immediately after the result of histopathology. Outcomes: Three months after treatment, dyspnea and hypoxemia improved, and he continued treatment. The patient was in a good clinical condition after 10 months of follow-up, but he died suddenly. As it is difficult to distinguish diffuse alveolar septal amyloidosis from other interstitial and granulomatous lung diseases because of their similar symptoms and imaging findings, thus, transthoracic sonar guided lung biopsy and histological examination is very important in the diagnosis of diffuse alveolar septal amyloidosis.

中文翻译：

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全身性AL淀粉样变性病伴弥漫性肺泡间隔侵犯和呼吸衰竭：一例病例报告并文献复习

淀粉样变性是淀粉样原纤维蛋白在任何组织或器官中的细胞外沉积。肺淀粉样变性病的临床表现是多变的，没有特定的症状。我们报告了罕见的弥漫性肺泡间隔淀粉样变性病，这是一种极为罕见的受累模式，预后很差，无法增进我们对该病的了解。一名27岁的男子抱怨呼吸急促和发。高分辨率计算机断层扫描显示双肺弥漫性毛玻璃样混浊，小叶间隔增厚。免疫组化显示单克隆λ轻链。该病例还显示出肾病综合征和心律不齐，提示肾脏和心脏受累。诊断：最终，通过经胸廓声纳引导下的肺活检（TSLB）确立了诊断，组织学检查显示9月肺泡中刚果红阳性无定形嗜酸性沉积物。干预措施：患者被送进呼吸重症监护病房，进行无创通气，然后接受家中氧气治疗出院，并在组织病理学检查后立即开始接受每日2 mg美法仑加泼尼松60 mg化疗。结果：治疗三个月后，呼吸困难和低氧血症得到改善，他继续治疗。随访10个月后，患者处于良好的临床状态，但突然死亡。