Dysproteinemia-Associated Kidney Diseases: Clinicopathological Correlations

Introduction: Dysproteinemia-associated kidney diseases can have diverse clinical and histological presentation but not all patients with monoclonal gammopathy have Monoclonal Gammopathy of Renal Significance (MGRS) and some have other causes for kidney lesions. Therefore, kidney biopsy is essential to make this diagnosis. We made a retrospective study, which aimed to: 1. Identify dysproteinemiaassociated kidney lesions; 2. Establish clinicopathological correlations of patients with those lesions and 3. Identify kidney and patient survival predictors. Methods: A retrospective, observational chart review of kidney biopsies performed, between January 2015 and February 2020, in three Portuguese Hospitals, to a total of 39 patients, with kidney lesions associated with monoclonal gammopathy, was undertaken. Results: The three main dysproteinemic kidney diseases identified were cast nephropathy, AL amyloidosis and Monoclonal Immunoglobulin Deposition Disease (MIDD), with different features among them. Only three patients fulfilled the criteria to Monoclonal Gammopathy of Renal Significance (MGRS). In regard to treatment, we verified that most of our patients were treated with chemotherapy. Unfortunately, only four recovered, either partially or completely. The mean kidney survival since kidney biopsy was 29,23 months and the mean patient survival since diagnosis was 24,46 months. Some clinical and pathologic features correlated to lowerkidney survival: acute tubular necrosis, cast nephropathy, Thrombotic Microangiopathy (TMA), haemoglobin and estimated Glomerular Filtration Rate (eGFR). Previous Nephrology follow-up correlated with higher kidney survival. Only eGFR was associated with lowerpatient survival.