Contributed by Douglas R. Johnson, MD
Published on line in August 2000
This 71 year-old non-diabetic man presented at admission in acute renal failure with heavy proteinuria following a several month history of ill-defined renal disease characterized by only mildly elevated creatinine levels. On examination, his blood pressure was 120/80, with mild lower extremity edema as the only significant clinical finding. He was on no current medications, and pertinent laboratory data included the following:
Routine serum electrophoresis and immunofixation assays detected a monoclonal lambda-restricted IgM paraprotein spike in the gamma region. The patient subsequently underwent a bone marrow biopsy which revealed involvement by a diffuse lymphoplasmacytic infiltrate (Images 01, 02, and 03). The lymphoid infiltrates were further characterized by immunoperoxidase stains to consist of predominantly CD20 positive cells (Image 04), with many IgM positive cells (Image 05), and equivalent numbers of lambda positive cells (Image 06). Rare admixed IgG positive plasma cells were present within the infiltrates (Image 07), along with a few kappa positive cells (Image 08). Occasional CD3 and CD43 positive cells, along with rare IgA positive cells were also noted. These results were interpreted as bone marrow involvement by a plasmacytoid lymphocyte / lymphoplasmacytic lymphoma (IgM lambda-restricted type) with concurrent Waldenstrom's macroglobulinemia.
The patient subsequently underwent renal ultrasonography and an abdominal CT scan which showed kidneys of normal size without abnormal signal intensity, cysts, or masses. A renal biopsy was performed, with the findings discussed below.
Four tan cylindrical renal core biopsies were received each measuring approximately 1.0 cm in length by 0.1 cm in average diameter. The specimens were divided appropriately for routine light microscopy, immunofluorescence microscopy, and electron microscopy.