Kidney Week

Abstract: TH-PO1094

Clinicopathological Spectrum of Kidney Biopsy Findings in Patients with a Solitary Kidney: 149 Cases over 20 Years

Session Information

• Pathology and Lab Medicine
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pathology and Lab Medicine

• 1700 Pathology and Lab Medicine

Authors

• Nakayama, Shingo, Cedars-Sinai, Los Angeles, California, United States

Shingo Nakayama, MD, PhD

• Kubota-Nakayama, Fumie, Cedars-Sinai, Los Angeles, California, United States

Fumie Kubota-Nakayama, MD, PhD

• Choung, Hae Yoon Grace, Cedars-Sinai, Los Angeles, California, United States

Hae Yoon Grace Choung, MD

• Lin, Mercury Y., Cedars-Sinai, Los Angeles, California, United States

Mercury Y. Lin, MD

• Hou, Jean, Cedars-Sinai, Los Angeles, California, United States

Jean Hou, MD

• Nast, Cynthia C., Cedars-Sinai, Los Angeles, California, United States

Cynthia C. Nast, MD, FASN

• Haas, Mark, Cedars-Sinai, Los Angeles, California, United States

Mark Haas, MD, PhD

• Yamashita, Michifumi, Cedars-Sinai, Los Angeles, California, United States

Michifumi Yamashita, MD, PhD, FASN

Background

A solitary kidney may result from congenital causes (e.g., unilateral renal agenesis, prevalence approximately 1 in 1,000) or acquired causes, most commonly nephrectomy for renal cell carcinoma or living kidney donation. Kidney biopsy of a solitary kidney was historically considered an absolute contraindication due to bleeding risk; however, accumulating evidence supports its reclassification as a relative contraindication, with the intervention risk reported at 0.3% in a recent meta-analysis of 118,064 native biopsies. Despite improved procedural safety, the clinicopathological characteristics of kidney biopsy in solitary kidney patients (Pts) remain poorly understood, with no dedicated case series published to date, leaving international guidelines without clear biopsy indications for this population.

Methods

We reviewed 52,868 native kidney biopsies evaluated at Cedars-Sinai Medical Center, Los Angeles, CA, USA, from January 1, 2006 to December 31, 2025.

Results

A total of 149 Pts (139 adults, 10 pediatric Pts) with a solitary kidney were identified. Median ages were 64.0 years (IQR 53.0–73.0) for adults and 13.5 years (IQR 10.0–16.0) for pediatric Pts. Females accounted for 40.3% of adults and 20.0% of pediatric Pts. In adults, secondary focal segmental glomerulosclerosis (2°FSGS) was the most common diagnosis, followed by acute tubular necrosis, diabetic glomerulosclerosis, membranous nephropathy, nephrosclerosis, pauci-immune crescentic glomerulonephritis, tubulointerstitial nephritis, IgA nephropathy, and lupus nephritis. 2°FSGS was also the most frequent diagnosis in pediatric Pts. Notably, 57/149 (38.3%; 55 adults and 2 pediatric) had kidney disease entities generally treated with steroids and/or immunosuppressive therapy; of these, 50/57 (87.7%) demonstrated relatively preserved renal parenchyma with low degrees of glomerulosclerosis and parenchymal scarring, suggesting they may be good candidates for immunosuppressive therapy.

Conclusion

This largest reported series of kidney biopsies in solitary kidney Pts demonstrates that 2°FSGS is the most prevalent diagnosis, with a diverse range of other glomerular, tubular, and vascular diseases also identified. A substantial proportion of Pts had treatable kidney disease with preserved renal parenchyma, suggesting that kidney biopsy in this population may directly inform therapeutic decisions and improve renal outcomes.