Yao Ying, Wang Su-Xia, Zhang You-Kang, Wang Yan, Liu Li, Liu Gang
Renal Division, Department of Medicine, Peking University First Hospital; Institute of Nephrology, Peking University; Key Laboratory of Renal Diseases, Ministry of Health of China, China.
Intern Med. 2014;53(2):121-4. doi: 10.2169/internalmedicine.53.0836. Epub 2012 Mar 1.
Light chain proximal tubulopathy is a rarely reported entity associated with plasma cell dyscrasia that classically manifests as acquired Fanconi syndrome and is characterized by the presence of κ-restricted crystals in the proximal tubular cytoplasm. We herein present a case of multiple myeloma with Fanconi syndrome and acute kidney injury due to light chain proximal tubulopathy with light chain cast nephropathy. Prominent phagolysosomes and numerous irregularly shaped inclusions with a fibrillary matrix in the cytoplasm of the proximal tubules were identified on electron microscopy. A monotypic light chain of the λ type was detected in the distal tubular casts, proximal tubular cytoplasmic lysosomes and fibrillary inclusions on immunofluorescence and immune electron microscopy. This case underscores the importance of conducting careful ultrastructural investigations and immunocytologic examinations of light chains for detecting and diagnosing light chain proximal tubulopathy.
轻链近端肾小管病是一种与浆细胞异常增生相关的罕见疾病，典型表现为获得性范科尼综合征，其特征是近端肾小管细胞质中存在κ限制晶体。我们在此报告一例因轻链近端肾小管病合并轻链管型肾病导致范科尼综合征和急性肾损伤的多发性骨髓瘤病例。电子显微镜检查发现近端肾小管细胞质中有突出的吞噬溶酶体和许多具有纤维状基质的不规则形状包涵体。免疫荧光和免疫电子显微镜检查在远端肾小管管型、近端肾小管细胞质溶酶体和纤维状包涵体中检测到λ型单克隆轻链。该病例强调了对轻链进行仔细的超微结构研究和免疫细胞检查对于检测和诊断轻链近端肾小管病的重要性。
