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Abstract: PO1909

Granulomatous Interstitial Nephritis Secondary to Chronic Lymphocytic Leukemia

Session Information

Category: Onco-Nephrology

  • 1500 Onco-Nephrology

Authors

  • Kurtz, Elizabeth C., University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
  • Castaner, Maricel, Allegheny Health Network, Pittsburgh, Pennsylvania, United States
  • Bastacky, Sheldon, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
  • Ahmad, Syeda B., University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
Introduction

Granulomatous interstitial nephritis (GIN) is a rare disorder defined by histological interstitial nephritis and interstitial granulomas. Common association includes medications, sarcoidosis, and infections. We present a less common case of GIN secondary to chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL).

Case Description

A 57 year old male with benign prostatic hypertrophy presented in early 2020 with leukopenia, lymphadenopathy, and sicca symptoms. A lymph node biopsy in March 2020 revealed non caseating granulomatous lymphadenitis diagnosed as sarcoidosis without clear pulmonary involvement and treated with steroids. His creatinine (Cr) was 0.83 mg/dL, calcium 9.5 mg/dL, white blood cell count of 2600, hemoglobin 12.6 g/dL, platelet count of 322,000, lactate dehydrogenase 1094 U/L, uric acid 8.3 mg/dL, negative SS-A/SS-B, negative Epstein Barr Virus, angiotensin converting enzyme 70 U/L, and a normal urinalysis.
In August 2020, his Cr rose to 4.24 mg/dL, with urine studies notable for 1+ protein and rare eosinophils. He had negative hepatitis B, hepatitis C, ANA, MPO, and PR3. His free kappa/lambda ratio was 1.89 (normal) and negative serum protein electrophoresis. PET/CT showed non-FDG avid diffuse lymphadenopathy. Renal biopsy revealed mesangial hypercellularity, severe interstitial inflammation, a lymphocyte predominant infiltrate with CD 20 positive B cells and non-caseating granulomas with eosinophils. He was diagnosed with GIN with atypical B cell lymphoid infiltrate. His prednisone dose was increased and he underwent a bone marrow biopsy revealing a CD5+ B cell lymphoproliferative disorder, consistent with Stage 4 CLL/SLL. Cytogenetics revealed trisomy 12 with significant bone marrow involvement, indicating an intermediate prognosis. He is being treated with Obinutuzumab and venetoclax with improvement in his Cr to 2.19 mg/dL.

Discussion

Our case report recapitulates findings from a prior case series in 2015. Search of University of Pittsburgh Pathology database from 2010-2020 yielded no patient with a diagnosis of GIN secondary to CLL. Our patient had partial renal recovery with steroids, obinutuzumab, and venetoclax indicating the efficacy of this regimen compared to rituximab, cyclophosphamide, and steroids. Our case highlights a rare entity of GIN that maybe underdiagnosed in patients with CLL.