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Abstract: PO1570

Vacuolated Denatured Casts Are a Distinct Type of Urinary Casts Associated with Severe Nephrotic Glomerulopathy

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Ramanand, Akanksh, Ochsner Medical Center - New Orleans, New Orleans, Louisiana, United States
  • Poloni, José A., Universidade do Vale do Rio dos Sinos, Sao Leopoldo, RS, Brazil
  • Sarkar, Abhirup, Suraksha Diagnostics, Kolkata, India
  • Giolo Franz, Ana Paula, Hospital de Clinicas de Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil
  • Velez, Juan Carlos Q., Ochsner Medical Center - New Orleans, New Orleans, Louisiana, United States
Background

Urinary casts identified through microscopic examination of the urinary sediment (MicrExUrSed) constitute clinically useful elements for the diagnosis of acute and chronic kidney pathologies. Granular, waxy and cellular casts are well characterized. However, a unique type of casts containing non-polarizable lipoid-like granules immersed within a lightly granular cast matrix is occasionally found. These casts have been labeled as vacuolated denatured casts (VDC). The clinical significance of VDC is not known. Herein, we present a case series of patients with specimens containing VDC.

Methods

We utilized an educational social media platform (Twitter) to probe for individual cases of VDC. We surveyed known educators who frequently post microphotographs of MicrExUrSed asking for filed cases of identification of VDC. Demographic and clinical characteristics were extracted and representative images were compiled for correct identification of VDC.

Results

Four urine microscopists (2 from South America, 1 from India, 1 from USA) contributed to the case series. A total of 12 cases were identified. Images were carefully reviewed to confirm identity of VDC. Median age 53 (27-78), 80% men, 50% had type 2 diabetes mellitus. Median serum creatinine at the time of MicrExUrSed was 3.6 (1.7-5.5) mg/dL. All (100%) patients had 3+ protein by urinary dipstick. Urine protein-to-creatinine ratio was in the nephrotic range in all 5 cases with available value [median 10.2 (3.3-11.8) g/g]. Concomitant findings included hematuria (58%), waxy casts (67%), granular casts (80%), fatty casts (42%) and renal tubular epithelial cells (58%). Histopathological diagnosis was available in 10 cases: 3 diabetic glomerulopathy, 3 focal segmental glomerulosclerosis, 2 transplant glomerulopathy, 1 membranous nephropathy and 1 advanced arterionephrosclerosis. Greater than 25% interstitial fibrosis was present in 6/10 (60%) cases.

Conclusion

VDC are a distinct type of casts that can be found in specimens of patients with advanced proteinuric glomerulopathy. The specific origin and composition of these casts remains unknown and requires further study.