Peer-reviewedCC BYFrontiers in nephrology6 Oct 2026

Case Report: Light chain amyloidosis in a patient with low-grade B-cell lymphoma.

Alex Matthaeus¹
David Thomas²
Hakan R Toka³

¹Graduate Medical Education (GME), Hospital Corporation of America (HCA) Blake Florida Hospital, Bradenton, FL, United States.
²NEPHROCOR, Bradenton, FL, United States.
³Manatee Kidney Diseases Consultants, Bradenton, FL, United States.

Abstract

Background

Light chain (AL) amyloidosis is typically associated with plasma cell dyscrasias but can rarely arise from low-grade B-cell non-Hodgkin lymphoma. Renal involvement may present with nephrotic-range proteinuria, acute kidney injury, edema, anasarca, and hypoalbuminemia. Recognizing lymphoma-associated AL amyloidosis is essential because diagnosis requires tissue confirmation, and treatment must target the underlying clonal B-cell disorder.Case

We report a rare case of severe renal AL amyloidosis in a patient with known low-grade B-cell non-Hodgkin lymphoma previously treated with rituximab. The patient presented with witnessed syncope, progressive peripheral edema, anasarca, and hypotension. Initial evaluation showed acute kidney injury with nephrotic-range proteinuria, including a urine protein-to-creatinine ratio greater than 10 g/g. Workup for autoimmune, infectious, and malignant causes of proteinuric kidney disease revealed positive hepatitis C antibody, mildly elevated serum lambda free light chains, a mildly decreased kappa-to-lambda ratio, and serum immunofixation positive for an IgM monoclonal lambda gammopathy. Renal biopsy demonstrated severe AL amyloidosis with predominant renal involvement. Bone marrow biopsy showed low-grade B-cell non-Hodgkin lymphoma involving 85% of the marrow, with CD20-positive immunophenotyping.Conclusion

This case highlights a rare presentation of renal AL amyloidosis secondary to low-grade B-cell non-Hodgkin lymphoma. Persistent nephrotic-range proteinuria in patients with B-cell lymphoma, particularly with IgM lambda monoclonal gammopathy, should prompt evaluation for amyloidosis with renal biopsy and hematologic assessment.

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BibTeX RIS

BibTeX

@article{matthaeus2026case,
  title = {{Case Report: Light chain amyloidosis in a patient with low-grade B-cell lymphoma.}},
  author = {Alex Matthaeus and David Thomas and Hakan R Toka},
  journal = {Frontiers in nephrology},
  year = {2026},
  month = oct,
  doi = {10.3389/fneph.2026.1959759},
  url = {https://europepmc.org/article/MED/42903237},
  note = {CC BY},
}

RIS

TY  - JOUR
TI  - Case Report: Light chain amyloidosis in a patient with low-grade B-cell lymphoma.
AU  - Alex Matthaeus
AU  - David Thomas
AU  - Hakan R Toka
PY  - 2026
DA  - 2026/10/06
JO  - Frontiers in nephrology
DO  - 10.3389/fneph.2026.1959759
UR  - https://europepmc.org/article/MED/42903237
AB  - Background  Light chain (AL) amyloidosis is typically associated with plasma cell dyscrasias but can rarely arise from low-grade B-cell non-Hodgkin lymphoma. Renal involvement may present with nephrotic-range proteinuria, acute kidney injury, edema, anasarca, and hypoalbuminemia. Recognizing lymphoma-associated AL amyloidosis is essential because diagnosis requires tissue confirmation, and treatment must target the underlying clonal B-cell disorder.Case  We report a rare case of severe renal AL amyloidosis in a patient with known low-grade B-cell non-Hodgkin lymphoma previously treated with rituximab. The patient presented with witnessed syncope, progressive peripheral edema, anasarca, and hypotension. Initial evaluation showed acute kidney injury with nephrotic-range proteinuria, including a urine protein-to-creatinine ratio greater than 10 g/g. Workup for autoimmune, infectious, and malignant causes of proteinuric kidney disease revealed positive hepatitis C antibody, mildly elevated serum lambda free light chains, a mildly decreased kappa-to-lambda ratio, and serum immunofixation positive for an IgM monoclonal lambda gammopathy. Renal biopsy demonstrated severe AL amyloidosis with predominant renal involvement. Bone marrow biopsy showed low-grade B-cell non-Hodgkin lymphoma involving 85% of the marrow, with CD20-positive immunophenotyping.Conclusion  This case highlights a rare presentation of renal AL amyloidosis secondary to low-grade B-cell non-Hodgkin lymphoma. Persistent nephrotic-range proteinuria in patients with B-cell lymphoma, particularly with IgM lambda monoclonal gammopathy, should prompt evaluation for amyloidosis with renal biopsy and hematologic assessment.
SN  - 2813-0626
ER  -

Abstract

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