Classically Light chain deposition disease(LCDD) presents with proteinuria ( almost in the nephrotic range). A recent article in NDT looks at a small cohort of patients that presented with LCDD with <0.5gm of proteinuria. They present 14 cases, average proteinuria was 0.3g/day. Most had CKD at baseline. IgG kappa was the most common light chain followed by IgM kappa. Only 3 patients had diagnostic myeloma, 2 had WM. Interestingly 5 had MGUS and 4 had smoldering myeloma. Serum creatinine decreased in most cases after chemotherapy was introduced. Proteinuria never became nephrotic range. This is thus far the largest series of such LCDD without proteinuria. Early identification of this atypical variant of LCDD is important. It seems also that it’s a smoldering form just like the hematologic counterpart and most of these patients had either MGUS or SM and not full blown MM.
What did the pathology show?- diffuse tubular basement membrane thickening; some with duplication. Rare casts were noted. Nodular sclerosis of GN lesions only in 2 cases and others did have some mesangial hypertrophy and ischemic lesions. No amyloidosis was noted in any cases.
Classically thought to be a proteinuric variant of myeloma, LCDD can also present as a non proteinuric disease mainly involving tubules.
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