Clinicopathologic spectrum of newly diagnosed multiple myeloma presenting with renal impairment: A tertiary care center experience from north India.

Multiple myeloma (MM) is a hematologic malignancy, characterized by the neoplastic proliferation of plasma cells producing a monoclonal immunoglobulin. Patients presents with signs and symptoms related to the infiltration of plasma cells into the bone or other organs or to kidney damage from excess light chains. Renal involvement with various presentations may be the first manifestation of the disease.All patients of MM presenting with renal dysfunction between July 2019 to June 2021 were included. Diagnosis of MM was made according to the 2014 guidelines of international myeloma working group.Out of total 144 cases of multiple myeloma renal involvement was present in 43 (29.8%). Mean age of study population was 55.49 years with 72% males. Most common clinical features were fatigue (59%), anorexia (47%) & edema (42%). Anemia was present in 79%, hypercalcemia in 16.2% and hyperuricemia in 20.9% patients. Renal failure was present in 72.1% with a mean eGFR 35.8 ml/min/1.73m2. Serum protein electrophoresis revealed M band in 81.4% and all except one patient had increased light chains in serum. Most common histological lesion were myeloma cast nephropathy (39.5%), primary amyloidosis (30.2%) & monoclonal immunoglobulin deposition disease (14%). Primary amyloidosis group had maximum 24-hour proteinuria and highest eGFR.The spectrum of renal involvement in multiple myeloma is heterogenous. It mainly affects middle and elderly age group. Typical clinical features might not be seen in all the cases and therefore a high index of suspicion in unexplained renal failure cases might help in early diagnosis and timely management.