Supplementary Material for: Long-term observation of focal segmental glomerulosclerosis after treatment of renal parenchymal malakoplakia: a case report

Introduction. Malakoplakia is a rare and chronic granulomatous disease that is pathologically characterized by the presence of Michaelis–Gutmann bodies and large macrophage clusters. Malakoplakia of the renal parenchyma is especially rare. In this report, we describe the long-term prognosis of a patient who was diagnosed with and treated for renal parenchymal malakoplakia in infancy.
Case Presentation. Seventeen years after malakoplakia onset, the patient presented to us with worsening proteinuria. Computed tomography revealed structural abnormalities in the kidney, and focal segmental glomerulosclerosis (FSGS) was diagnosed based on renal biopsy findings. No Michaelis–Gutmann bodies were observed in von Kossa-stained biopsy specimens. Regular outpatient monitoring during the next 9 years showed gradual deterioration of renal function and a moderately high protein/creatinine ratio.
Conclusion. Our findings suggest that structural changes due to malakoplakia can cause focal segmental glomerulosclerosis. Moreover, structural changes indicate the healing of malakoplakia in infancy and the disappearance of its characteristic lesions over time. Owing to its long-term observation period, this unique case provides new insights into the outcomes of patients with renal parenchymal malakoplakia.

引言。软化斑（Malakoplakia）是一种罕见的慢性肉芽肿性疾病，病理学特征为存在迈克尔-古特曼小体（Michaelis–Gutmann bodies）及大量巨噬细胞簇。肾实质软化斑尤为罕见。本报告详述了1例婴儿期确诊并接受治疗的肾实质软化斑患者的长期预后情况。

病例报告。软化斑发病17年后，该患者因蛋白尿进行性加重就诊于我院。计算机断层扫描（Computed tomography, CT）显示肾脏存在结构异常，结合肾活检病理结果，确诊为局灶节段性肾小球硬化（focal segmental glomerulosclerosis, FSGS）。冯·科萨染色（von Kossa-stained）的活检标本中未检测到迈克尔-古特曼小体。后续9年的定期门诊随访结果显示，患者肾功能逐渐恶化，尿蛋白肌酐比值呈中度升高。

结论。本研究结果提示，软化斑所致的肾脏结构改变可诱发局灶节段性肾小球硬化。此外，此类结构改变提示婴儿期罹患的软化斑已愈合，其特征性病变随时间推移逐渐消失。由于本病例拥有较长的随访观察周期，这一独特案例为肾实质软化斑患者的临床转归提供了新的认识。