Fig. 1

Light microscopic images of the renal biopsy

(a–d) Normal glomeruli but diffuse and extensive interstitial infiltration with medium- to large-sized atypical lymphoid cells were observed in periodic acid–Schiff staining (a: × 100, b: × 400), periodic acid–methenamine–silver staining (c: × 400), and hematoxylin and eosin staining (d: × 400). (e–h) Immunostaining showed that lymphocytic cells were positive for CD3 (e), Ki-67 (g), and terminal deoxynucleotidyl transferase (h), but negative for CD20 (f)