Kidney Week

Abstract: FR-PO0479

Glomerular Crystal-Storing Histiocytosis with Concurrent Light-Chain Proximal Tubulopathy in IgA Kappa Monoclonal Gammopathy of Renal Significance

Session Information

• AKI: Case Reports - TMA, Vasculitis, Immune-Mediated Injury, and Systemic Disease
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Carey, Austin L., Southern Illinois University School of Medicine, Springfield, Illinois, United States

Austin L. Carey, MD

• Sweis, Jaleel Jerry, Southern Illinois University School of Medicine, Springfield, Illinois, United States

Jaleel Jerry Sweis, MD

• Adekola, Bemi, Southern Illinois University School of Medicine, Springfield, Illinois, United States

Bemi Adekola, MD

• Rich, Trent E., Southern Illinois University School of Medicine, Springfield, Illinois, United States

Trent E. Rich, MD

Introduction

Crystal-storing histiocytosis (CSH) is a rare disorder that is characterized by the accumulation of crystallized immunoglobulin light chains within histiocytes. This is commonly associated with underlying monoclonal gammopathies. Renal involvement is uncommon and is most commonly localized to the renal interstitium. The presence of crystalline inclusions within the glomerular capillary lumen is particularly rare. Recognition of renal CSH is important because it may represent a manifestation of monoclonal gammopathy of renal significance (MGRS) requiring clone-directed therapy.

Case Description

A 64-year-old male with a history of HTN, HLD, T2DM, and hep C presented with oliguric AKI, abdominal pain, and anemia. Ultimately, progressing to AKI-D. Serum studies demonstrated an IgA kappa monoclonal gammopathy on immunofixation with monoclonal light chains detected on urine protein electrophoresis. Immunoglobulin G and M levels were mildly decreased, and β2-microglobulin was elevated. Kidney biopsy revealed CSH, with glomeruli containing many geometric-shaped crystals within the capillary lumen. CD68 stain-positive cells revealed crystals. Pronase IF studies showed positive staining for kappa light chains. Electron microscopy demonstrated numerous large geometric crystals within the glomerular capillary lumen, interstitium, and tubular epithelial cells. Findings were consistent with CSH of kappa light-chain type, light chain proximal tubulopathy (LCPT), kappa light chain type, and interstitial hemorrhage. Bone marrow biopsy revealed a normocellular marrow (40%) with trilineage hematopoiesis and a mild increase in plasma cells (5–9%) without evidence of monoclonality by immunohistochemistry or flow cytometry. Cytogenetic analysis demonstrated an isolated loss of the Y chromosome. FISH testing was negative for myeloma-associated abnormalities. PET imaging showed no FDG-avid lesions. The patient was treated with clone-directed therapy using bortezomib and dexamethasone. Following treatment, kidney function improved, and dialysis was successfully discontinued.

Discussion

Glomerular CSH with LCPT is a rare renal manifestation of MGRS. Recognition of crystalline inclusions on a kidney biopsy is essential for diagnosis. With the timely initiation of clone-directed therapy, renal recovery is possible, even in patients requiring dialysis at presentation.