Yan-Fei Ng
1 
, Chang-Yin Choinh
2 , Marvin Raden Torres De Guzman
3 , Chandramouli Nagarajan
3 , Hwai-Liang Loh
1* 1 Department of Anatomical Pathology, Singapore General Hospital, Singapore
2 Department of Renal Medicine, Changi General Hospital, Singapore
3 Department of Haematology, Singapore General Hospital, Singapore
Abstract
Light chain proximal tubulopathy (LCPT) is an uncommon renal disease characterized by the accumulation of monoclonal light chains within proximal tubular epithelial cells, with or without crystal formation. We report a rare case of lambda LCPT with crystals. Renal biopsy showed substantial acute tubular injury with unusual cytoplasmic changes affecting proximal tubules. In addition, abnormal tubular casts suggested concomitant light chain cast nephropathy. A clonal plasma cell infiltrate was present in the tubulointerstitial compartment. Immunofluorescence demonstrated strong staining for lambda light chain in tubular epithelial cells. Despite the absence of discernible crystals on light microscopy (LM), they were readily identified when ultrastructural evaluation was undertaken. Crystalline inclusions demonstrated positive immunogold labelling for lambda.
Implication for health policy/practice/research/medical education:
Histopathological recognition and accurate diagnosis of light chain proximal tubulopathy is very important as it may be the first sign of an underlying serious hematological condition for which early treatment is needed.
Please cite this paper as: Ng YF, Chionh CY, De Guzman MRT, Nagarajan C, Loh HL. Lambda light chain crystalline proximal tubulopathy with probable light chain cast nephropathy and clonal plasma cell infiltrate – uncommon manifestations of a rare form of multiple myeloma. J Nephropathol. 2021;10(1):e08. DOI: 10.34172/jnp.2021.08.