增生性肾小球肾炎伴轻链型单克隆免疫球蛋白沉积

Light chain only variant of proliferative glomerulonephritis with monoclonal immunoglobulin deposits

慢性起病的中年男性患者,肾脏表现为大量蛋白尿、少量镜下血尿、肾功能减退,伴高血压、轻度贫血、低补体血症,血游离轻链κ/λ比值增高,骨髓细胞学示浆细胞8.0%,骨髓细胞流式检测示2.3%κ轻链型单克隆浆细胞。肾活检病理示肾小球结节样病变,免疫荧光单一κ轻链及C3沉积,电镜下系膜区较多、基膜内皮下大量、上皮侧散在无特殊结构的电子致密物沉积。最终诊断为增生性肾小球肾炎伴轻链型单克隆免疫球蛋白沉积。

A 42-year-old man presented with nephrotic-range proteinuria and hematuria,renal dysfunction,hypertension,decreased serum C3,anemia,elevatedκ/λratio,8%plasmacytosis in bone marrow biopsy.Kidney biopsy showed proliferative glomerulonephritis with nodular pattern.Immunoflurerscence indicated restrictedκlight chain and C3 distributed in glomerular capillary wall and mesangial with granular appearance.The electron-dense deposits without substructure were identified predominately in subendothelial,mesangial and occasional in subepithelial region by electron microscopy.The final diagnosis was light chain only variant of proliferative glomerulonephritis with monoclonal immunoglobulin deposits.