Monoclonal protein detected in the serum of asymptomatic patients is defined as monoclonal gammopathy of undetermined significance (MGUS). When associated with renal disorders, the presence of a circulating monoclonal protein (M-protein) is referred to as monoclonal gammopathy of renal significance (MGRS). The prevalence of MGRS is not well studied, but it has been estimated to be as low as 1.5% in in a study of 2955 patients with MGUS [
1]. The type of renal injury associated with monoclonal gammopathy includes a variety of patterns, likely related to the structural characteristics of the M protein, and classification of this group of renal diseases is based on pathologic features [
2,
3]. The clinical presentation and differential diagnosis in MGRS can be challenging as exemplified by this unusual case. …
