Berger病或IgA肾病。如箭头所示，IgA主要沉积在系膜，使系膜细胞增生。IgA肾病常表现为血尿。
This is Berger's disease, or IgA nephropathy. The IgA is deposited mainly in mesangium, which then increases mesangial cellularity as shown at the arrow. Patients with IgA nephropathy usually present with hematuria.
