Kidney Week

Abstract: SA-PO0748

Atypical Kikuchi Disease-Like Interstitial Necroinflammation on Kidney Biopsy in a Patient Subsequently Diagnosed with Lupus

Session Information

• Glomerular Diseases: Lupus Nephritis, Monoclonal Gammopathy-Related Disease, and Transplantation
  October 24, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Dougherty, Jacob, Oregon Health & Science University, Portland, Oregon, United States

Jacob Dougherty, DO, MPH

• Deodhar, Atul A., Oregon Health & Science University, Portland, Oregon, United States

Atul A. Deodhar, MD, MBBS

• Kung, Vanderlene Liu, Oregon Health & Science University, Portland, Oregon, United States

Vanderlene Liu Kung, MD, PhD

• Troxell, Megan L., Stanford University School of Medicine, Stanford, California, United States

Megan L. Troxell, MD, PhD

• Avasare, Rupali S., Oregon Health & Science University, Portland, Oregon, United States

Rupali S. Avasare, MD

• Dunlap, Jennifer, Oregon Health & Science University, Portland, Oregon, United States

Jennifer Dunlap, MD

• Andeen, Nicole K., Oregon Health & Science University, Portland, Oregon, United States

Nicole K. Andeen, MD

Introduction

Kikuchi-Fujimoto disease, or histiocytic necrotizing lymphadenitis, most commonly affects younger patients of Asian descent and can have clinical and pathologic overlap with autoimmune disease particularly systemic lupus erythematosus, infectious, and malignant lymphadenopathies.

Case Description

A 20-year-old female presented with lower extremity purpuric rash initially thought to be IgA vasculitis. She had a history of joint pains affecting large rather than smaller joints and no malar rash. Workup revealed positive ANA, dsDNA, SSA, SSB, Smith, low C3 and C4, pancytopenia, and lymphadenopathy with normal creatinine, microscopic hematuria, and uPCR of 0.61.

Kidney biopsy (Figure) demonstrated an atypical hematopoietic interstitial infiltrate composed of medium to large cells with prominent apoptosis and expression of monocytic markers. Glomeruli showed segmental endocapillary hypercellularity or intraluminal plugs of eosinophilic material (in 10%) suggesting a circulating cryoglobulin. No tissue was submitted for frozen IF or EM, but paraffin IF showed modest mesangial staining for IgM only. The overall findings were concerning for an underlying hematolymphoid malignancy versus unusual autoimmune phenomenon.

Subsequent extensive infectious and hematologic workup were negative, including a lymph node biopsy which demonstrated reactive lymphoid proliferation without necrotizing lymphadenitis. A type III cryoglobulin (IgG and IgM) in serum was later identified. Taken together, the patient was diagnosed with lupus and cryoglobulinemia and treated with hydroxychloroquine, mycophenolate, and prednisone with initial improvement but extra-renal flare at 6 months.

Discussion

We describe a highly unusual kidney biopsy with limited glomerular involvement and a prominent Kikuchi-like interstitial infiltrate which was concerning for hematologic malignancy, in a young patient subsequently diagnosed with lupus. To our knowledge, this phenomenon has been described only in abstract form (3 cases, USCAP 2014 by Dr. Josephine Ambruzs et al) with no published reports. As hematologic malignancies may also present with immune phenomenon, this atypical presentation of lupus on kidney biopsy represents an important diagnostic pitfall.