Renal heavy and light chain amyloidosis: A rare case report.

RATIONALE: Renal heavy and light chain amyloidosis (AHL) is a rare disease primarily diagnosed through renal biopsy. Here, we report a patient with renal AHL. The decision to report this case stems from its rarity. This case provides a reference for the diagnosis and management of this disease.

PATIENT CONCERNS: A 58-year-old man was admitted to the nephrology department in May 2024 with the chief complaint of lower limb edema over the past year, which had worsened in the preceding 3 months. The clinical presentation included nephrotic syndrome and renal insufficiency.

DIAGNOSIS: The definitive diagnosis was established after comprehensive laboratory tests, bone marrow biopsy, renal pathology, and mass spectrometry analysis.

INTERVENTIONS: After a definitive diagnosis, the patient was treated with chemotherapy using a combination of bortezomib, dexamethasone, and cyclophosphamide.

OUTCOMES: The patient's renal function continued to deteriorate, ultimately leading to hemodialysis treatment.

LESSONS: Renal AHL, even though rare, needs to be considered strongly in elderly patients presenting with nephrotic syndrome and renal insufficiency. Cardiac involvement is uncommon. After active treatment, the prognosis is better than that of light chain amyloidosis.