Table of Contents
ISRN Pathology
Volume 2012 (2012), Article ID 541075, 6 pages
http://dx.doi.org/10.5402/2012/541075
Clinical Study

Light Chain Proximal Tubulopathy: Expanding the Pathologic Spectrum with and without Deposition of Crystalline Inclusions

1Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
2Department of Pathology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
3Department of Nephrology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA

Received 16 July 2012; Accepted 29 July 2012

Academic Editors: R. Drut, K. Honda, T. Kovács, C.-R. Lai, and F. Maffini

Copyright © 2012 Shree G. Sharma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Light chain proximal tubulopathy (LCPT) is an uncommon form of renal disease associated with dysproteinemias. It is characterized by intracytoplasmic deposition of crystallized mostly kappa monoclonal light chains in proximal tubules (PTs). Crystals are located within lysosomes by electron microscopy (EM). Rare lambda LCPT cases without crystals by EM were described. Retrospectively, we reviewed clinical, light microscopic (LM), immunofluorescence (IF), and EM findings in 9 cases) (8 males, 1 female; mean age 57 years (38–81)) with multiple myeloma. LM showed abundant cytoplasmic droplets in PT cells in all cases. Droplets were also present in the podocytes, endothelial and parietal cells in one case. IF revealed staining of crystals with kappa in 3 and lambda in 6. EM showed electron dense rectangular, rhomboid, or needle shaped crystals in PT cells in 3 cases (33%), one of which had crystals in podocytes and interstitial cells. Six lambda LCPT cases showed no crystals by EM (67%). This may reflect differences in the physicochemical properties of light chains. The mechanisms of crystal accumulation in these cells and the significance of this finding are unknown.