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Kidney Week

Abstract: TH-PO713

Rituximab in the Treatment of Thymoma-Related Minimal Change Disease

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Author

  • Nie, Yuxin, Zhongshan Hospital Fudan University, Shanghai, Shanghai, China
Introduction

Thymoma may cause autoimmune-related kidney disease. This article presents two cases of thymoma-related kidney disease treated with oral prednisone in combination with rituximab. Remission of proteinuria were achieved, and shrinkage of the thymoma mass was observed on the CT scan.

Case Description

Case 1: A 67y male was admitted because of foamy urine and edema. Lab tests revealed hypoalbuminemia and proteinuria. Scr increased progressively, while auto-immune antibodies were negative. Chest CT showed a mass in the anterior mediastinum. The patient underwent a right posterior hepatic lobectomy in 2020.The pathology revealed a thymoma type B2. Other past history includes hypertension and diabetes. Based on the patient's clinical manifestations, history of thymoma, and renal biopsy, the patient was diagnosed as thymoma-related minimal change disease, acute interstitial inflammation, diabetic nephropathy, and hypertensive kidney injury. Methylprednisolone was administered 240mg/d *3d, followed by prednisone 30mg/d and rituximab 375mg/m2/week *4 weeks. Remission was achieved one month after completion of the RTX course. Surprisingly, the thymoma shrank on the CT scan.
Case 2: A 67y male was admitted because of foamy urine and edema. Lab tests showed a 24h urine protein of 8.78g. Plasma albumin was 16.9g/L, eGFR was 53mL/min/1.73 m2. The patient claimed a history of thymoma, and underwent thymectomy in 2014. PET-CT showed left pleural, left phrenic angle and cardiophrenic angle lymph node, and anterior chest wall subcutaneous metastases. The patient claim a history of hypertension. The final diagnosis based on clinical manifestations and renal biopsy was thymoma-related MCD, hypertensive kidney injury, and AIN. Steroid therapy (methylprednisolone 120mg/d*3d, followed by prednisone 40mg/d) combined with RTX (375mg/m2/week *4weeks) was administered. The patient’s proteinuria gradually decreased two months after RTX treatment, the urine protein was 0.67 g/24h at the latest follow-up. In addition, there was remission of the patient’s thymoma metastasis.

Discussion

Experience in treating thymoma-related nephropathy with RTX is limited, our cases report the effectiveness of RTX in both MCD and thymoma. This report provide a new approach for treating thymoma-related kidney disease, especially for those who are not suitable for surgery.