Bilateral Testicular Plasmacytoma Preceding Multiple Myeloma with Extramedullary Renal Involvement: A Case Report

Multiple myeloma (MM) is a clonal proliferation of plasma cells in the bone marrow, with criteria including bone marrow plasma cells ≥10% or biopsy-proven plasmacytoma with myeloma-defining events. Solitary plasmacytoma (SP) represents a singular clonal plasma cell lesion without myeloma-defining events, while extramedullary disease (EMD) is an aggressive form of MM characterized by independent growth outside the bone marrow microenvironment. We present a unique case of a 64-year-old patient with bilateral testicular plasmacytoma anteceding the development of Immunoglobulin G (IgG) kappa-type MM, featuring extramedullary renal involvement.