Proliferative glomerulonephritis with unusual, organized, cylindrical deposits associated with angioimmunoblastic...

We describe an elderly man who developed angioimmunoblastic lymphadenopathy-like T-cell lymphoma, followed by acute renal failure 2 months later. Renal biopsy revealed proliferative glomerulonephritis, which was characterized by enlarged glomeruli with increased cellularity, thickened capillaries, intracapillary inflammatory cells, focal necrosis, and fibrin extravasation. Immunofluorescence studies revealed capillary and mesangial deposits of IgG, IgM, IgA, Ig kappa, Ig lambda, and C3. Electron microscopy revealed unusual, organized, electron-dense deposits in the capillary walls and mesangium. The deposits occurred as accumulations of large rigid tubules or cylinders, which, in longitudinal section, were double-walled. In transverse section, the deposits were annular or horseshoe shaped and occasionally had a central filament. The morphologic characteristics of these deposits are different from those seen in cryoglobulinemia or fibrillary and immunotactoid glomerulopathies. The significance of these deposits is uncertain; they may represent a cryoglobulin or an abnormal serum protein related to angioimmunoblastic lymphadenopathy-like T-cell lymphoma. The findings in this case expand the morphologic spectrum of glomerular lesions that may be associated with malignant lymphoproliferative disorders and, particularly, angioimmunoblastic lymphadenopathy-like T-cell lymphoma.