(a) Gross examination from the partial nephrectomy specimen showing a relatively well circumscribed, firm, homogenous, white mass in the renal hilum (white bar = 1 cm), (b) low power showing a diffuse lymphoplasmacytic infiltrate associated with fibrosis that infiltrate between glomeruli, (c) medium power showing prominent fibrosis, and (d) IgG4 immunohistochemistry showing numerous IgG4+ plasma cells surrounding a glomerulus. No IgG4 positive plasma cells were identified in the glomerulus.
