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Kidney Week

Abstract: PO0176

A Rare Case of Obstructive Nephropathy with Intratubular Tamm-Horsfall Polyps Secondary to Acquired Hemophilia

Session Information

  • AKI Mechanisms - 1
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Trainee Case Report

  • 103 AKI: Mechanisms

Authors

  • Meissner, Kyle, University of Texas Health Science Center at Houston, Houston, Texas, United States
  • Musa, Amal, University of Texas Health Science Center at Houston, Houston, Texas, United States
  • Reddy, Vikas D., University of Texas Health Science Center at Houston, Houston, Texas, United States
  • Suo, Liye, University of Texas Health Science Center at Houston, Houston, Texas, United States
  • Glass, William F., University of Texas Health Science Center at Houston, Houston, Texas, United States
  • Teakell, Jade M., University of Texas Health Science Center at Houston, Houston, Texas, United States
Introduction

Acquired hemophilia has been rarely implicated in obstructive nephropathy. We present a case of gross hematuria, bilateral hydronephrosis, and biopsy-confirmed tubulointerstitial nephritis with intratubular Tamm-Horsfall Protein (THP) polyps. These atypical pathological aggregations of urinary glycoproteins were previously described to be located in renal veins or lymphatics. Our case represents a rare etiology of obstructive nephropathy, with unique pathological findings, secondary to an acquired hemophilia.

Case Description

A 64-year-old man with hypertension and tobacco use presented with bilateral flank pain and gross hematuria. Urinalysis showed hematuria, pyuria, and proteinuria. He had oliguric acute kidney injury (AKI) with creatinine (Cr) of 3.2 mg/dL. Renal ultrasound showed bilateral hydronephrosis. Renal function deteriorated over 3 days to Cr of 7.4 mg/dL with proteinuria of 10 g/day. Serologic markers revealed mildly elevated PR3-ANCA. Pulse steroid therapy was begun and kidney biopsy was performed. Pathology report described acute tubulointerstitial nephritis with THP polyps and interstitial non-caseating granulomas. Immunohistochemistry assay showed THP polyps within markedly dilated renal tubules, consistent with obstructive nephropathy. No glomerulitis or vasculitis was seen.

After biopsy, the patient developed retroperitoneal hemorrhage requiring embolization. Further studies indicated the presence of a factor VIII inhibitor. He improved with transition from steroids to mycophenolate mofetil. A few months later, his renal function returned to normal with a bland urinalysis, proteinuria less than 100mg/day and resolution of hydronephrosis.

Discussion

We encountered a rare presentation of acquired hemophilia with macroscopic hematuria and AKI. We suspect that bladder clots and associated intraluminal clots resulted in elevated tubular pressures causing obstructive nephropathy and the formation of intratubular THP polyps. Administration of immunosuppressive therapy decreased tubulointerstitial inflammation as well as factor VIII inhibitor production, reinforcing our hypothesis. Anti-factor VIII antibodies are a rare complication of solid tumors and urologic malignancy work-up is ongoing.