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Kidney Week

Abstract: TH-PO697

THSD7A-Related Membranous Nephropathy (MN) in a Patient with Prostate Adenocarcinoma

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Author

  • Kaur, Harpreet, Alameda Health System, Oakland, California, United States
Introduction

Thrombospondin type-1 domain- containing 7A (THSD7A) is a transmembrane protein expressed on the podocytes that serves as an auto-antigen in patients with membranous nephropathy. We report a case of kidney biopsy proven THSD7A associated MN in a 69-year-old Vietnamese male with history of metastatic prostate adenocarcinoma and chronic Hepatitis B.

Case Description

A 69-year-old male admitted for weight loss was found to have retroperitoneal lymphadenopathy, diffuse mixed sclerotic and lytic lesion, and enlarged prostate. He underwent EUS with FNA of retroperitoneal adenopathy which showed metastatic prostate cancer. Then two months later, patient presented with marked anasarca for two weeks. He was afebrile, normotensive and saturating well on RA. Labs notable for albumin 1.6, UA with >1000 mg/dL proteinuria, urine protein/creatinine 18.68, Hepatitis B surface antigen reactive, Hepatitis B core antibody reactive, and PSA 833. Phospholipase A2 Receptor (PLA2R) antibody was negative and THSD7A antibody was positive. Subsequently had a kidney biopsy which showed membranous nephropathy, grade I. He was initially suspected to have secondary MN due to cancer and untreated HBV, but kidney biopsy stain pattern more reflective of primary THSD7A MN likely related to his cancer. He was started on both Hepatitis B treatment (with Entecavir) and prostate cancer (with Lupron and Enzalutamide), Bumex, Metolazone and anticoagulation with Lovenox. While waiting for Rituximab approval, patient was started on Ponticelli regimen [Protocol: cyclophosphamide and alternate with prednisone for 6 months total (month 1, 3, 5, prednisone 0.5kg/day, then 2, 4, 6 cyclophosphamide 2mg/kg/day), with Bactrim prophylaxis]. Once the Rituximab was approved, Ponticelli regimen was stopped after the first month and prednisone was tapered. He has finished Rituximab induction therapy and currently on every 6 months maintenance. Current urine protein/Creatinine ratio remains elevated at 13. Hepatitis B is well-controlled and PSA is now 0.5.

Discussion

In a meta-analysis of 10 studies involving 4121 participants, the prevalence of THSD7A was on average 3% in all patients and higher at 10% in PLA2-R patients. Another study discovered that 8 of 40 patients developed a malignancy within a median time of 3 months from diagnosis of MN. Thus it is important to screen and monitor for malignancies in THSD7-A positive MN patients.