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Abstract: PO1906

Membranous Nephropathy Preceding the Recurrence of Thymoma

Session Information

Category: Trainee Case Report

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials


  • Lamba, Perola, Rogosin Institute, New York, New York, United States
  • Epstein, David L., Weill Cornell Medicine, New York, New York, United States

Membranous nephropathy secondary to neoplastic processes is a recognized phenomenon, and it may be the first finding that leads to the diagnosis of the underlying malignancy. Here, we describe a case of secondary MN in a patient with a history of recurrent thymoma that led to a prompt evaluation for malignancy, which did not appear on PET imaging until a few months later.

Case Description

We describe the case of a 62 year old man with myasthenia gravis (on IVIG), history of thymoma with recurrence in 2017 and March 2019 requiring multiple surgeries and adjuvant chemoradiation. There was no evidence of disease in October 2019. Subsequently, he presented in December 2019 with anasarca, acute kidney injury and nephrotic syndrome (proteinuria greater than 9 g per day). He underwent diuresis and a kidney biopsy which was notable for secondary membranous nephropathy with negative PLA2R antibody. A PET-CT was performed in December 2019 which did not show any evidence of FDG avidity or active malignancy. In February 2020, he presented with worsening anasarca and a myasthenic flare, for which he was treated with steroids, five sessions of plasma exchange and rituximab. In order to search for possible recurrent thymoma, he had another PET-CT which found a new FGD avid focus in the left second rib, which was biopsied and consistent with recurrent thymoma. He was then treated with radiation therapy.


When a patient is diagnosed with secondary membranous nephropathy without an identifiable cause, it is recommended to perform general screening for cancers. In order to compare conventional screening with PET imaging, Z Feng et al compared two groups of patients with different screening approaches. In this study the PET imaging group identified 5 cases of malignancy among 49 patients, while the conventional screening only identified 1 case of malignancy among 75 patients. While PET imaging may be the optimal imaging for undiagnosed malignancy or recurrent malignancy in patients with newly diagnosed membranous nephropathy, this case presentation suggests that thymoma recurrence with nephrotic syndrome may precede a positive result on PET imaging.
Reference: Z Feng, S Wang, Y Huang et al. “A follow-up analysis of positron emission tomography/computed tomography in detecting hidden malignancies at the time of diagnosis of membranous nephropathy” Oncotarget 2016. 7(9): 9645-9651