Amyloid Cast Nephropathy

Cases of light chain cast nephropathy occasionally show amyloid staining properties including positive staining for Congo red with green birefringence upon polarization. The significance of this staining in light chain casts is largely undetermined though, when present, it is sometimes referred to as “amyloid cast nephropathy”. A recent case series found that that intratubular amyloid was significantly associated with the occurrence of systemic light chain amyloidosis (5/13 in the ‘intratubular amyloid’ group vs 0/30 in the ‘no intratubular amyloid’ group, P=0.001). Thus, when present in light chain cast nephropathy, a work-up to examine for the possibility of systemic disease is warranted.

Gibier, et al. Intratubular amyloid in light chain cast nephropathy is a risk factor for systemic light chain amyloidosis. Mod Pathol. 2017 Oct 20. [Epub ahead of print] PMID: 29052601