Clinicopathologic and Outcome Characteristics of Glomerulopathy With Striated Deposits: A Case Series

Glomerulopathy with striated deposits (GSD) is a rare entity defined by ultrastructural deposits with striated substructure. Prior data were limited to case reports. This case series characterizes GSD's clinicopathologic spectrum and prognosis.

Case series.

Eighteen GSD cases identified from the nephropathology archives of Mayo Clinic and Columbia University, 2011-2025.

Fifty percent of the patients were male, 78% were Caucasian, and their median age was 73 years. Most patients presented with CKD (median creatinine, 2.6 mg/dl), proteinuria (median, 3.8 g/day), and hematuria (80%), a minority (29%) with hypocomplementemia, and none with extrarenal manifestations. Fifteen (88%) patients had hematologic conditions, primarily (56%) monoclonal gammopathy of renal significance (MGRS). Histologically, most cases (67%) had a membranoproliferative glomerulonephritis pattern on biopsy. All exhibited striated ultrastructural deposits of regularly stacked straight electron-dense bands (13 nm in mean diameter) with distinctive periodicity (mean 20 nm), which were present mostly in subendothelial and mesangial regions. Ten (56%) cases exhibited monotypic Ig glomerular deposits (IgGκ in 7) on immunofluorescence (IF), which were masked in 6 (60%), requiring IF evaluation using pronase-digested paraffin tissue for unmasking. Six of these 10 patients (60%) had a circulating MIg whose isotype matched the deposited Igs. The remaining cases exhibited polytypic Ig glomerular deposits (4 cases) or had no detectable Ig (4 cases) identified histologically. After follow-up (median 14 months) in 15 patients, 6 (40%) progressed to kidney failure within a median of 11 months, including 1 with recurrence in a kidney allograft. Kidney response to clone-directed therapy was observed in all 4 evaluable patients.

Retrospective design, small sample size.

GSD is a rare heterogeneous glomerulopathy presenting in older patients with CKD and proteinuria, and frequently associated with hematologic conditions, particularly MGRS. We propose adding GSD with monotypic Ig deposits to the spectrum of MGRS lesions. Further studies are needed to elucidate precise deposit composition(s) and effective therapeutic approaches.