case_images: PMC10894454_01
case_images: Renal pathology findings of light and electron microscopy.. (A) Mild mesangial hypercellularity was observed in glomeruli (arrowhead) (PAS staining). (B, C) The tubulointerstitium showed inflammatory cell infiltration and tubulitis (PAS staining). (D) Electron microscopy showed electron-dense deposits in mesangial area (arrow). PAS: periodic acid-Schiff
case_images: cureus-0016-00000052981-i01.jpg
case_images: PMC10894454_01_cureus-0016-00000052981-i01.jpg
case_images: FIG1
case_images: There were no active lesions such as crescent formation or endocapillary proliferation (Figure 1A), whereas the tubular interstitium was partially edematous and infiltrated with inflammatory cells, and tubulitis was observed (Figure 1B, 1C). Deposition in the mesangial area was revealed by electron microscopy (Figure 1D).
case_images: Renal pathology findings of immunofluorescence microscopy.  IgA (3+) and C3 (2+) were predominantly positive in the mesangial area. IgM (1+) was weakly positive in the same area.
case_images: cureus-0016-00000052981-i02.jpg
case_images: PMC10894454_01_cureus-0016-00000052981-i02.jpg
case_images: FIG2
case_images: Immunofluorescence staining showed predominant positivity for IgA (3+) and C3 (2+) in the mesangial area (Figure 2).
case_images: The clinical course of the patient. eGFR: estimated glomerular filtration rate; HPF: high power field; U-RBC: urinary red blood cell
case_images: cureus-0016-00000052981-i03.jpg
case_images: PMC10894454_01_cureus-0016-00000052981-i03.jpg
case_images: FIG3
case_images: The patient was prescribed prednisolone 50 mg/day (Figure 3).