Polyoma virus
The patient was a 32 year old man, 4 years post-renal-transplant, with a recent rise in serum creatinine. An
H&E stained section (on the left) from a needle biopsy shows tubular epithelial cells with enlarged nuclei; one cell
shows a nuclear inclusion with ground glass appearance surrounded by a halo. In other sections there were foci
of interstitial fibrosis with tubular atrophy and inflammatory infiltrate composed of lymphocytes and histiocytes.
Immunohistochemical stain for polyoma virus (shown on the right) was positive; stains for CMV and HSV were negative.
Contributed by Dr. Li Wang and Dr. Alfredo Esparza