CASE 18: Polyomavirus Nephropathy

69-year-old man status post deceased donor kidney transplant for NSAIDs-related chronic tubulo-interstitial disease 10 months prior to current presentation. Azathioprine had to be discontinued due to pancytopenia. Corticosteroids were started. A biopsy was obtained to evaluate an elevated creatinine level.

Biopsy reveals extensive inflammation with frequent tubulitis (Figures 112-70 and 112-71). Some tubular epithelial cells reveal enlarged nuclei with viral inclusions. SV40 polyomavirus stain is positive in nuclei of infected cells by immunoperoxidase technique (Figure 112-72).