Renal Disorders Associated with Waldenström Macroglobulinaemia, IgM MGUS and IgM-Producing B-Cell Lymphoproliferative Disorders

Abstract

Renal disorders are uncommonly associated with IgM MGUS and Waldenström macroglobulinaemia (WM). Data are limited to large case series that suggest that related renal involvement occurs in 5% of patients with WM. Although uncommon, there is a much greater variety of renal pathologies associated with WM and IgM MGUS than that seen in patients with multiple myeloma, where cast nephropathy predominates. In WM, uncommonly direct infiltration of the renal system by lymphoma or cast nephropathy with a high light-chain level can occur. AL amyloidosis can present with nephrotic syndrome as a feature with IgM MGUS or WM. Cryoglobulinaemia and light-chain deposition disease are other important potential causes of renal impairment with IgM MGUS and WM. There are other rarer monoclonal gammopathy of renal significance (MGRS) conditions characterised by typically isolated kidney disease that are causally related to a B-cell or plasma-cell clonal disorder usually in a precancerous MGUS state, although in some renal pathologies, the association is less clear. Central to the majority of these diagnoses is the need for an accurate renal histological diagnosis, and management requires close joint working of renal and haematology teams.