Zhang Fangcheng, Shen Qi, Sun Xiaoling, Long Xiao, Cheng Dan
Department of Pathology, Center of Ultrapathology, Renmin Hospital of Wuhan University, Wuhan, China.
Department of Operating Room, Zhongnan Hospital of Wuhan University, Wuhan, China.
BMC Nephrol. 2025 Jul 8;26(1):364. doi: 10.1186/s12882-025-04315-9.
Collagen type III glomerulopathy (CG) is a rare idiopathic nephropathy characterized by the massive deposition of dense, fractured, curved, band-like fibers in the mesangial and subendothelial regions. Ultrastructural pathological examination confirms that these deposits are composed of type III collagen. Here, we report two rare cases of CG: Patient I was superimposed with membranous nephropathy (MN), and Patient II was superimposed with diabetic nephropathy (DN), both confirmed by transmission electron microscopy (EM).
Both patients presented with bilateral lower extremity edema of unknown etiology. Patient I was admitted to the hospital multiple times due to persistent proteinuria. The phospholipase A2 receptor (PLA2R) test was positive, but there was no response to steroid treatment. Patient II has a 10-year history of hypertension and fasting hyperglycemia. Renal biopsies revealed segmental aggregation of homogeneous substances beneath the mesangium and endothelial cells. To obtain a definitive diagnosis, biopsy specimens were transferred to our department for electron microscopic evaluation.
This study highlights the ultrastructural characteristics of CG and emphasizes the indispensable role of electron microscopy in the diagnosis of CG, particularly when coexisting with other glomerular diseases. The Early EM examination in renal biopsies is crucial for a clear diagnosis and prognosis prediction.
III型胶原肾小球病（CG）是一种罕见的特发性肾病，其特征是在系膜和内皮下区域大量沉积致密、断裂、弯曲的带状纤维。超微结构病理检查证实这些沉积物由III型胶原组成。在此，我们报告两例罕见的CG病例：病例I合并膜性肾病（MN），病例II合并糖尿病肾病（DN），均经透射电子显微镜（EM）证实。
两名患者均出现病因不明的双侧下肢水肿。病例I因持续性蛋白尿多次入院。磷脂酶A2受体（PLA2R）检测呈阳性，但对类固醇治疗无反应。病例II有10年高血压和空腹血糖升高病史。肾活检显示系膜和内皮细胞下有均质物质节段性聚集。为明确诊断，活检标本被送至我科进行电子显微镜评估。
本研究突出了CG的超微结构特征，并强调了电子显微镜在CG诊断中的不可或缺作用，尤其是在与其他肾小球疾病共存时。肾活检早期进行EM检查对于明确诊断和预测预后至关重要。
