PROLIFERATIVE GLOMERULONEPHRITIS WITH UNUSUAL, ORGANIZED, CYLINDRICALDEPOSITS ASSOCIATED WITH ANGIOIMMUNOBLASTIC LYMPHADENOPATHY-LIKE T-CELL LYMPHOMA

We describe an elderly man who developed angioimmunoblastic lymphadeno pathy-like T-cell lymphoma, followed by acute renal failure 2 months l ater. Renal biopsy revealed proliferative glomerulonephritis, which wa s characterized by enlarged glomeruli with increased cellularity, thic kened capillaries, intracapillary inflammatory cells, focal necrosis, and fibrin extravasation. Immunofluorescence studies revealed capillar y and mesangial deposits of IgG, IgM, IgA, Ig kappa, Ig lambda, and C3 . Electron microscopy revealed unusual, organized, electron-dense depo sits in the capillary walls and mesangium. The deposits occurred as ac cumulations of large rigid tubules or cylinders, which, in longitudina l section, were double-walled. In transverse section, the deposits wer e 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 glomeru lopathies. The significance of these deposits is uncertain; they may r epresent a cryoglobulin or an abnormal serum protein related to angioi mmunoblastic lymphadenopathy-like T-cell lymphoma. The findings in thi s case expand the morphologic spectrum of glomerular lesions that may be associated with malignant lymphoproliferative disorders and, partic ularly, angioimmunoblastic lymphadenopathy-like T-cell lymphoma.