Monoclonal Gammopathy of Renal Significance: Histomorphological Spectrum at a Tertiary Care Center

Abstract

Introduction: The term Monoclonal gammopathy of renal significance (MGRS) has been described to include patients with renal manifestations associated with circulating monoclonal proteins with or without a clonal lymphoproliferation (B-cell or Plasma cell) and not meeting diagnostic criteria of an overt hematological malignancy. A host of MGRS associated lesions have been described that involve various renal compartments. Our study describes the histo-morphological spectrum of MGRS cases at our centre in the last 05 years and description as per the classification system of International Kidney and Monoclonal Gammopathy Research group (IKMG) Material and methods: Retrospective analysis was carried out of all the renal biopsies with characteristic Monoclonal Immunoglobulin (MiG) lesions for histopathological diagnosis between years 2015 to 2020 and reviewed by two independent pathologists. Results: Most patients in the study belonged to the fifth decade with a median age of 50 years (mean 50.14 +10.43) range (24-68 years) with a male preponderance. Most patients presented with proteinuria as the sole manifestation (66.6%). Many of the patients (48%) had an M spike by Serum Protein Electrophoresis (SPEP) or Urinary Protein electrophoresis (UPEP) with abnormal serum free light chain assay (60.8%). AL Amyloidosis was the most common diagnosis observed on histopathological evaluation (68.7%) followed by Light Chain Deposition Disease (LCDD) (10.4%). Conclusion: MGRS lesions are infrequently encountered in the practice of nephropathology and pose a diagnostic challenge due to limitation of a congruent clinical or hematological picture. A thorough histological examination with immunofluorescence and electron microscopy often precipitates in the right diagnosis and prompts timely management.

Renal Amyloidosis Secondary to Monoclonal Gammopathy of Renal Significance in a Young Patient: A Case Report

“…In addition, AL amyloidosis is witnessed in MGRS patients above 50 years of age. 3 However, our patient was only 30 years old, signifying this case’s clinical importance. Further, the diagnostic approaches adapted to identify this case would also guide the clinicians to trace the onset and progression of amyloidosis in young patients.…”

“…Various Indian research studies have documented the prevalence of MGUS or the predisposition of MGRS in aged individuals. 3,15,16 However, there are no reports on the predominance of MGRS or its association with renal amyloidosis in young individuals. To the best of our knowledge, this is the first report of MGRS-associated renal amyloidosis in a young Indian.…”

“…In addition, the predisposition of renal amyloidosis in MGRS patients occurs at a later age. 3 But the possibility of both these disorders has not been traced in young individuals. Herein, we report the first case of MGRS-associated amyloid light chain (AL) amyloidosis in a young Indian.…”