Paraneoplastic immunoglobulin A nephropathy and associated focal segmental glomerulosclerosis in asymptomatic low volume B-cell lymphoma - a case report

Abstract

Background: Paraneoplastic glomerulonephritis is rare in haematological malignancies and tends to manifest as minimal change disease, membranous glomerulonephritis or membranoproliferative glomerulonephritis. We present the first report of immunoglobulin A nephropathy and associated focal segmental glomerulosclerosis in a patient with asymptomatic low grade B-cell lymphoma.

Case presentation: A 53 year old gentleman presented with nephrotic range proteinuria (urine protein creatinine ratio of 662 mg/mmol) on a background of type 2 diabetes mellitus (glycosylated haemoglobin: < 6%), hypertension, obesity (body mass index: 47.6 kg/m²) and degenerative spine disease. Bone marrow biopsy diagnosed a low grade B-cell lymphoma and renal biopsy was consistent with immunoglobulin A nephropathy. Lymphoma treatment with six cycles of cyclophosphamide/ rituximab/ prednisolone led to normalisation of urinary protein excretion (urine protein creatinine ratio: 14 mg/mmol at 26 months post-chemotherapy).

Conclusion: Paraneoplastic immunoglobulin A nephropathy can occur with a broad range of haematological malignancies regardless of stage. This case illustrates the importance of meticulous haematological system work-up for patients presenting with immunoglobulin A nephropathy. Recognition of paraneoplastic immunoglobulin A nephropathy and early diagnosis of associated malignancy can be life-saving.

Keywords: Glomerulonephritis; Immunoglobulin A nephropathy; Lymphoma; Non-Hodgkin; Paraneoplastic; Proteinuric.

Fig. 1

Timeline of clinical presentation, investigations and treatment. It is likely that the patient’s proteinuria initiated in 2013 and urine protein:creatinine ratio peaked at 662 mg/mmol prior to his first renal outpatient review in October, 2014. His second renal biopsy completed in February 2015 identified immunoglobulin A nephropathy (IgAN) and associated focal segmental glomerulosclerosis (FSGS). Bone marrow aspirate and trephine completed in March 2015 demonstrated low-grade B-cell lymphoma as the cause of his persistent abnormal serum electrophoresis pattern. Chemotherapy led to improvement in both serum electrophoresis pattern and urine protein excretion

Fig. 2

Kidney biopsy. a Light microscopy shows an area of segmental glomerular scarring with a foam cell and adhesion to Bowman’s capsule (upper right) away from the glomerular hilum. (Periodic acid–Schiff stain, 400× magnification). b Immunofluorescence shows mesangial reactivity of moderate intensity in two glomeruli. (200× magnification). c This electron microscopic image shows diffuse epithelial foot effacement over the basement membrane of three glomerular capillary loops. There is also podocytic swelling with focal microvillous transformation. (8,000× magnification)