Immunoglobulin M Nephropathy: A Diagnostic Dilemma Between Minimal Change Disease and Focal Segmental Glomerulosclerosis.

Immunoglobulin M nephropathy (IgMN) is an idiopathic glomerulonephritis characterized by diffuse IgM deposits in the mesangium and mesangial hypercellularity. It has been a controversial diagnosis since it was initially described, as IgMN shares features with both minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). However, studies have shown that IgMN is a distinct clinicopathological diagnosis comprising patients with predominant mesangial IgM deposits and who do not meet established criteria for MCD and FSGS. We present a case of a 24-year-old male presenting with hypertension and proteinuria, with kidney biopsy showing concern for IgMN. These patients carry a significant risk of developing nephrotic syndrome, renal insufficiency, and progression to end-stage renal failure. This underscores the importance of timely diagnosis of IgMN and therapeutic intervention to prevent kidney function decline. Management options include corticosteroids or calcineurin inhibitors, with some evidence on the use of rituximab for refractory cases. There is a need for further research on IgMN to establish standardized treatment protocols and long-term outcomes for patients with IgMN.